import GraphiQLIDE from '@site/src/components/GraphiQLIDE';

Postgres: Aggregation Queries

Aggregate fields

You can fetch aggregations on columns along with nodes using an aggregation query.

The name of the aggregate field is of the form <field-name> + _aggregate.

Common aggregation functions are count, sum, avg, max, min, etc. You can see the complete specification of the aggregate field in the API reference. Note that not all aggregation functions are available for all data types.

:::info Note

For more advanced use cases, you can use views or custom SQL functions.

:::

Fetch aggregated data of an object

Example: Fetch a list of articles with aggregated data of their rating:

<GraphiQLIDE query={query { articles_aggregate { aggregate { count sum { rating } avg { rating } max { rating } } nodes { id title rating } } }} response={{ "data": { "articles_aggregate": { "aggregate": { "count": 10, "sum": { "rating": 26 }, "avg": { "rating": 2.6 }, "max": { "rating": 4 } }, "nodes": [ { "id": 1, "title": "sit amet", "rating": 1 }, { "id": 2, "title": "a nibh", "rating": 3 }, { "id": 3, "title": "amet justo morbi", "rating": 4 }, { "id": 4, "title": "vestibulum ac est", "rating": 2 }, { "id": 5, "title": "ut blandit", "rating": 2 }, { "id": 6, "title": "sapien ut", "rating": 1 }, { "id": 7, "title": "nisl duis ac", "rating": 4 }, { "id": 8, "title": "donec semper sapien", "rating": 3 }, { "id": 9, "title": "sit amet", "rating": 3 }, { "id": 10, "title": "dui proin leo", "rating": 3 } ] } } }} />

Fetch aggregated data on nested objects {#pg-nested-aggregate}

The following is an example of a nested object query with aggregations on the array relationship between an author and articles.

Example: Fetch author with id "1" and a nested list of articles with aggregated data of their rating:

<GraphiQLIDE query={query { authors (where: {id: {_eq: 1}}) { id name articles_aggregate { aggregate { count avg { rating } max { rating } } nodes { id title rating } } } }} response={{ "data": { "authors": [ { "id": 1, "name": "Justin", "articles_aggregate": { "aggregate": { "count": 2, "avg": { "rating": 2.5 }, "max": { "rating": 4 } }, "nodes": [ { "id": 15, "title": "vel dapibus at", "rating": 4 }, { "id": 16, "title": "sem duis aliquam", "rating": 1 } ] } } ] } }} />