TRUNC

Truncates the specified date or time.

Truncates the specified date or time. If you omit the precision argument, TRUNC truncates to day (DD) precision.

Behavior type

  • Immutable if thetarget date is a TIMESTAMP or DATE

  • Stable if the target date is aTIMESTAMPTZ

Syntax

TRUNC( trunc-target[, 'precision'] )

Parameters

*trunc-target*
An expression that evaluates to one of the following data types:
precision
A string constant that specifies precision for the truncated value, one of the following:

  • Century: CC | SCC

  • Year: SYYY | YYYY | YEAR | YYY | YY | Y

  • ISO Year: IYYY | IYY | IY | I

  • Quarter: Q

  • Month: MONTH | MON | MM | RM

  • Same weekday as first day of year: WW

  • Same weekday as first day of ISO year: IW

  • Same weekday as first day of month: W

  • Day (default): DDD | DD | J

  • First weekday: DAY | DY | D

  • Hour: HH | HH12 | HH24

  • Minute: MI

  • Second: SS

Examples

Truncate to the current hour:

=> => SELECT TRUNC(CURRENT_TIMESTAMP, 'HH');
        TRUNC
---------------------
 2016-04-29 10:00:00
(1 row)

Truncate to the month:

=> SELECT TRUNC('9-22-2011 12:34:00'::TIMESTAMP, 'MM');
   TIMESTAMP_TRUNC
---------------------
 2011-09-01 00:00:00
(1 row)

See also

TIMESTAMP_TRUNC