TIMESTAMP / TIMESTAMPTZ

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The TIMESTAMP and TIMESTAMPTZ data types store a date and time pair in UTC.

Variants

TIMESTAMP has two variants:

• TIMESTAMP presents all TIMESTAMP values in UTC.

• TIMESTAMPTZ converts TIMESTAMP values from UTC to the client's session time zone (unless another time zone is specified for the value). However, it is conceptually important to note that TIMESTAMPTZ does not store any time zone data.

  Note:

  The default session time zone is UTC, which means that by default TIMESTAMPTZ values display in UTC.

The difference between these two variants is that TIMESTAMPTZ uses the client's session time zone, while the other simply does not. This behavior extends to functions like now() and extract() on TIMESTAMPTZ values.

You can use the timezone() and AT TIME ZONE functions to convert a TIMESTAMPTZ into a TIMESTAMP at a specified timezone, or to convert a TIMESTAMP into a TIMESTAMPTZ at a specified timezone.

Best practices

We recommend always using the TIMESTAMPTZ variant because the TIMESTAMP variant can sometimes lead to unexpected behaviors when it ignores a session offset. However, we also recommend you avoid setting a session time zone offset for your database.

Aliases

In CockroachDB, the following are aliases:

• TIMESTAMP, TIMESTAMP WITHOUT TIME ZONE
• TIMESTAMPTZ, TIMESTAMP WITH TIME ZONE

Syntax

A constant value of type TIMESTAMP/TIMESTAMPTZ can be expressed using an interpreted literal, or a string literal annotated with type TIMESTAMP/TIMESTAMPTZ or coerced to type TIMESTAMP/TIMESTAMPTZ.

TIMESTAMP constants can be expressed using the following string literal formats:

To express a TIMESTAMPTZ value (with time zone offset from UTC), use the following format: TIMESTAMPTZ '2016-01-25 10:10:10.555555-05:00'

When it is unambiguous, a simple unannotated string literal can also be automatically interpreted as type TIMESTAMP or TIMESTAMPTZ.

Note that the fractional portion is optional and is rounded to microseconds (6 digits after decimal) for compatibility with the PostgreSQL wire protocol.

For PostgreSQL compatibility, CockroachDB bounds TIMESTAMP values by the lowest and highest TIMESTAMP values supported by PostgreSQL. The minimum allowable TIMESTAMP value is 4714-11-24 00:00:00+00 BC, and the highest allowable TIMESTAMP value is 294276-12-31 23:59:59.999999.

Size

A TIMESTAMP/TIMESTAMPTZ column supports values up to 12 bytes in width, but the total storage size is likely to be larger due to CockroachDB metadata.

Precision

CockroachDB supports precision levels from 0 (seconds) to 6 (microseconds) for TIMESTAMP/TIMESTAMPTZ values. Precision in time values specifies the number of fractional digits retained in the seconds field. For example, specifying a TIMESTAMPTZ value as TIMESTAMPTZ(3) truncates the time component to milliseconds. By default, TIMESTAMP/TIMESTAMPTZ values have a precision of 6 (microseconds).

You can use an ALTER COLUMN ... SET DATA TYPE statement to change the precision level of a TIMESTAMP/TIMESTAMPTZ-typed column. If there is already a non-default precision level specified for the column, the precision level can only be changed to an equal or greater precision level. For an example, see Create a table with a TIMESTAMP-typed column, with precision.

Examples

Create a table with a TIMESTAMPTZ-typed column

> CREATE TABLE timestamps (a INT PRIMARY KEY, b TIMESTAMPTZ);

> SHOW COLUMNS FROM timestamps;

  column_name |  data_type  | is_nullable | column_default | generation_expression |  indices  | is_hidden
+-------------+-------------+-------------+----------------+-----------------------+-----------+-----------+
  a           | INT8        |    false    | NULL           |                       | {primary} |   false
  b           | TIMESTAMPTZ |    true     | NULL           |                       | {}        |   false
(2 rows)

> INSERT INTO timestamps VALUES (1, TIMESTAMPTZ '2016-03-26 10:10:10-05:00'), (2, TIMESTAMPTZ '2016-03-26');

> SELECT * FROM timestamps;

  a |             b
+---+---------------------------+
  1 | 2016-03-26 15:10:10+00:00
  2 | 2016-03-26 00:00:00+00:00
(2 rows)

Create a table with a TIMESTAMP-typed column, with precision

> CREATE TABLE timestamps (a INT PRIMARY KEY, b TIMESTAMP(3));

> SHOW COLUMNS FROM timestamps;

  column_name |  data_type   | is_nullable | column_default | generation_expression |  indices  | is_hidden
--------------+--------------+-------------+----------------+-----------------------+-----------+------------
  a           | INT8         |    false    | NULL           |                       | {primary} |   false
  b           | TIMESTAMP(3) |    true     | NULL           |                       | {}        |   false
(2 rows)

> INSERT INTO timestamps VALUES (1, TIMESTAMP '2020-03-25 12:00:00.123456'), (2, TIMESTAMP '2020-03-26 4:00:00.123456');

> SELECT * FROM timestamps;

  a |               b
----+--------------------------------
  1 | 2020-03-25 12:00:00.123+00:00
  2 | 2020-03-26 04:00:00.123+00:00
(2 rows)

To change the precision level of a column, you can use an ALTER COLUMN ... SET DATA TYPE statement:

> ALTER TABLE timestamps ALTER COLUMN b SET DATA TYPE TIMESTAMP(4);

ALTER TABLE

> SHOW COLUMNS FROM timestamps;

  column_name |  data_type   | is_nullable | column_default | generation_expression |  indices  | is_hidden
--------------+--------------+-------------+----------------+-----------------------+-----------+------------
  a           | INT8         |    false    | NULL           |                       | {primary} |   false
  b           | TIMESTAMP(4) |    true     | NULL           |                       | {}        |   false
(2 rows)

When changing precision level, TIMESTAMP can be changed to TIMESTAMPTZ, and TIMESTAMPTZ can be changed to TIMESTAMP:

> ALTER TABLE timestamps ALTER COLUMN b SET DATA TYPE TIMESTAMPTZ(5);

ALTER TABLE

> SHOW COLUMNS FROM timestamps;

  column_name |   data_type    | is_nullable | column_default | generation_expression |  indices  | is_hidden
--------------+----------------+-------------+----------------+-----------------------+-----------+------------
  a           | INT8           |    false    | NULL           |                       | {primary} |   false
  b           | TIMESTAMPTZ(5) |    true     | NULL           |                       | {}        |   false
(2 rows)

In this case, the b column, which is of type TIMESTAMPTZ(5), cannot be changed to a precision level below 5:

> ALTER TABLE timestamps ALTER COLUMN b SET DATA TYPE TIMESTAMPTZ(3);

ERROR: unimplemented: type conversion from TIMESTAMPTZ(5) to TIMESTAMPTZ(3) requires overwriting existing values which is not yet implemented
SQLSTATE: 0A000

Supported casting and conversion

TIMESTAMP values can be cast to any of the following data types:

Infinity TIMESTAMP casts

CockroachDB currently does not support an infinity/-infinity representation for TIMESTAMP casts. Instead, infinity::TIMESTAMP evaluates to 294276-12-31 23:59:59.999999+00:00, the maximum TIMESTAMP value supported, and -infinity::TIMESTAMP evaluates to -4713-11-24 00:00:00+00:00, the minimum TIMESTAMP value supported.

Note that this behavior differs from PostgreSQL, for which infinity is higher than any allowable TIMESTAMP value (including 294276-12-31 23:59:59.999999+00:00), and -infinity is lower than any allowable TIMESTAMP value (including -4713-11-24 00:00:00+00:00).

For more details, see tracking issue.

See also

Data Types

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