WHERE keyword

WHERE clause filters data. Filter expressions are required to return boolean result.

QuestDB includes a JIT compiler for SQL queries which contain WHERE clauses.

Syntax

The general syntax is as follows. Specific filters have distinct syntaxes detailed thereafter.

Logical operators

QuestDB supports AND, OR, NOT as logical operators and can assemble conditions using brackets ().

SELECT * FROM table
WHERE
a = 1 AND (b = 2 OR c = 3 AND NOT d);

Symbol and string

QuestDB can filter strings and symbols based on equality, inequality, and regular expression patterns.

Exact match

Evaluates match of a string or symbol.

SELECT * FROM users
WHERE name = 'John';

Does NOT match

Evaluates mismatch of a string or symbol.

SELECT * FROM users
WHERE name != 'John';

Regular expression match

Evaluates match against a regular expression defined using java.util.regex patterns.

SELECT * FROM users WHERE name ~ 'Jo';

Regular expression does NOT match

Evaluates mismatch against a regular expression defined using java.util.regex patterns.

SELECT * FROM users WHERE name !~ 'Jo';

List search

Evaluates match or mismatch against a list of elements.

SELECT * FROM users WHERE name in('Tim', 'Tom');

SELECT * FROM users WHERE NOT name in('Tim', 'Tom');

Numeric

QuestDB can filter numeric values based on equality, inequality, comparison, and proximity.

:::note

For timestamp filters, we recommend the timestamp search notation which is faster and less verbose.

:::

Equality, inequality and comparison

SELECT * FROM users WHERE age >= 23;

SELECT * FROM users WHERE age = 23;

SELECT * FROM users WHERE age != 23;

Boolean

Using the columnName will return true values. To return false values, precede the column name with the NOT operator.

SELECT * FROM users WHERE isActive;

SELECT * FROM users WHERE NOT isActive;

Timestamp and date

QuestDB supports both its own timestamp search notation and standard search based on inequality. This section describes the use of the timestamp search notation which is efficient and fast but requires a designated timestamp.

If a table does not have a designated timestamp applied during table creation, one may be applied dynamically during a select operation.

Native timestamp format

QuestDB automatically recognizes strings formatted as ISO timestamp as a timestamp type. The following are valid examples of strings parsed as timestamp types:

Exact timestamp

Syntax

SELECT * FROM scores WHERE ts = '2010-01-12T00:02:26.000Z';

SELECT * FROM scores WHERE ts = '2010-01-12T00:02:26.000000Z';

Time range (WHERE IN)

Returns results within a defined range.

:::tip Recommended: TICK syntax

For complex timestamp filtering, use TICK interval syntax. TICK handles date ranges, business days, timezones, and schedules in a single expression:

-- Last 5 business days, 9:30 AM New York time, 6.5 hour windows
WHERE ts IN '[$today-5bd..$today-1bd]T09:30@America/New_York#workday;6h30m'

With exchange calendars (Enterprise), you can filter by real exchange schedules including holidays and early closes:

-- NYSE trading hours for January, holidays excluded automatically
WHERE ts IN '2025-01-[01..31]#XNYS'

:::

Syntax

SELECT * FROM scores WHERE ts IN '2018';

SELECT * FROM scores WHERE ts IN '2018-05-23T12:15';

Time range with interval modifier

You can apply a modifier to further customize the range. The modifier extends the upper bound of the original timestamp based on the modifier parameter. An optional interval with occurrence can be set, to apply the search in the given time range repeatedly, for a set number of times.

Syntax

• timestamp is the original time range for the query.

• modifier is a signed integer modifying the upper bound applying to the timestamp:

  • A positive value extends the selected period.
  • A negative value reduces the selected period.

• interval is an unsigned integer indicating the desired interval period for the time range.

• repetition is an unsigned integer indicating the number of times the interval should be applied.

Examples

Modifying the range:

SELECT * FROM scores WHERE ts IN '2018;1M';

The range is 2018. The modifier extends the upper bound (originally 31 Dec 2018) by one month.

SELECT * FROM scores WHERE ts IN '2018-01;-3d';

The range is Jan 2018. The modifier reduces the upper bound (originally 31 Jan 2018) by 3 days.

Modifying the interval:

SELECT * FROM scores WHERE ts IN '2018-01-01;1d;1y;2';

The range is extended by one day from Jan 1 2018, with a one-year interval, repeated twice. This means that the query searches for results on Jan 1-2 in 2018 and in 2019:

A more complete query breakdown would appear as such:

-- IN extension for time-intervals

SELECT * FROM trades WHERE timestamp in '2023'; -- whole year
SELECT * FROM trades WHERE timestamp in '2023-12'; -- whole month
SELECT * FROM trades WHERE timestamp in '2023-12-20'; -- whole day

-- The whole day, extending 15s into the next day
SELECT * FROM trades WHERE timestamp in '2023-12-20;15s';

-- For the past 7 days, 2 seconds before and after midnight
SELECT * from trades WHERE timestamp in '2023-09-20T23:59:58;4s;-1d;7'

IN with multiple arguments

Syntax

IN with more than 1 argument is treated as standard SQL IN. It is a shorthand of multiple OR conditions, i.e. the following query:

SELECT * FROM scores
WHERE ts IN ('2018-01-01', '2018-01-01T12:00', '2018-01-02');

is equivalent to:

SELECT * FROM scores
WHERE ts = '2018-01-01' or ts = '2018-01-01T12:00' or ts = '2018-01-02';

BETWEEN

Syntax

For non-standard ranges, users can explicitly specify the target range using the BETWEEN operator. As with standard SQL, both upper and lower bounds of BETWEEN are inclusive, and the order of lower and upper bounds is not important so that BETWEEN X AND Y is equivalent to BETWEEN Y AND X.

SELECT * FROM scores
WHERE ts BETWEEN '2018-01-01T00:00:23.000000Z' AND '2018-01-01T00:00:23.500000Z';

BETWEEN can accept non-constant bounds, for example, the following query will return all records older than one year before the current date:

SELECT * FROM scores
WHERE ts BETWEEN to_str(now(), 'yyyy-MM-dd')
AND dateadd('y', -1, to_str(now(), 'yyyy-MM-dd'));

Inclusivity example

Inclusivity is precise, and may be more granular than the provided dates appear.

If a timestamp in the format YYYY-MM-DD is passed forward, it is computed as YYYY-MM-DDThh:mm:ss.sss.

To demonstrate, note the behaviour of the following example queries:

SELECT *
FROM trades
WHERE timestamp BETWEEN '2024-04-01' AND '2024-04-03'
LIMIT -1;

The query pushes to the boundaries as far as is possible, all the way to: 2024-04-02T23:59:59.9947212.

If there was an event at precisely 2024-04-03T00:00:00.00000, it would also be included.

Now let us look at:

SELECT *
FROM trades
WHERE timestamp BETWEEN '2024-04-01' AND '2024-04-03T00:00:00.99'
LIMIT -1;

Even with fractional seconds, the boundary is inclusive.

A row with timestamp 2024-04-03T00:00:00.990000Z would also return in boundary.