WEEK_ISO

Returns the week of the year for the specified date as an integer, where the first week starts on Monday and contains January 4. This function conforms with the ISO 8061 standard.

Syntax

WEEK_ISO ( date )

Behavior type

• Immutable if thespecified date is a TIMESTAMP, DATE, or VARCHAR

• Stable if the specified date is aTIMESTAMPTZ

Parameters

date

The date to process, one of the following data types:

• VARCHAR
• DATE
• TIMESTAMP
• TIMESTAMPTZ

Examples

The first week of 2016 begins on Monday January 4:

=> SELECT WEEK_ISO ('1-4-2016'::DATE);
 WEEK_ISO
----------
        1
(1 row)

January 3 2016 returns week 53 of the previous year (2015):

=> SELECT WEEK_ISO ('1-3-2016'::DATE);
 WEEK_ISO
----------
       53
(1 row)

In 2015, January 4 is on Sunday, so the first week of 2015 begins on the preceding Monday (December 29 2014):

=> SELECT WEEK_ISO ('12-29-2014'::DATE);
 WEEK_ISO
----------
        1
(1 row)