jstests/query_golden/expected_output/lookup_unwind.md
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
{ "_id" : 1, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
{ "_id" : 2, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
{ "_id" : 3, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
{ "_id" : 1, "index" : null, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
{ "_id" : 2, "index" : null, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
{ "_id" : 3, "index" : null, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : "$cities"
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 4, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true
}
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 4, "index" : null, "name" : "Romania" }
[
{
"$match" : {
"name" : "USA",
"_id" : {
"$gt" : 0
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 10, "cityName" : "New York", "countryId" : 1 }, "index" : NumberLong(0), "name" : "USA" }
{ "_id" : 1, "cities" : { "_id" : 11, "cityName" : "Los Angeles", "countryId" : 1 }, "index" : NumberLong(1), "name" : "USA" }
[
{
"$match" : {
"name" : "Canada",
"nonExistentField" : {
"$exists" : false
}
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
{ "_id" : 2, "cities" : { "_id" : 12, "cityName" : "Toronto", "countryId" : 2 }, "index" : NumberLong(0), "name" : "Canada" }
[
{
"$match" : {
"$and" : [
{
"name" : "France"
},
{
"_id" : 3
}
]
}
},
{
"$lookup" : {
"from" : "cities",
"localField" : "_id",
"foreignField" : "countryId",
"as" : "cities"
}
},
{
"$unwind" : {
"path" : "$cities",
"preserveNullAndEmptyArrays" : true,
"includeArrayIndex" : "index"
}
}
]
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
{ "_id" : 3, "cities" : { "_id" : 13, "cityName" : "Paris", "countryId" : 3 }, "index" : NumberLong(0), "name" : "France" }
[jsTest] ---- [jsTest] Ran 2304 queries [jsTest] ----