Categories:: Date & time functions

DATE_FROM_PARTS¶

Creates a date from individual numeric components that represent the year, month, and day of the month.

Aliases:: DATEFROMPARTS

Syntax¶

DATE_FROM_PARTS( <year>, <month>, <day> )

Arguments¶

year: The integer expression to use as a year for building a date.
month: The integer expression to use as a month for building a date, with January represented as 1, and December as 12.
day: The integer expression to use as a day for building a date, usually in the 1-31 range.

Usage notes¶

DATE_FROM_PARTS is typically used to handle values in “normal” ranges (e.g. months 1-12, days 1-31), but it also handles values from outside these ranges. This allows, for example, choosing the N-th day in a year, which can be used to simplify some computations.

Year, month, and day values can be negative (e.g. to calculate a date N months prior to a specific date). The behavior of negative numbers is not entirely intuitive; see the Examples section for details.

Examples¶

Components in normal ranges:

SELECT DATE_FROM_PARTS(1977, 8, 7);
+-----------------------------+
| DATE_FROM_PARTS(1977, 8, 7) |
|-----------------------------|
| 1977-08-07                  |
+-----------------------------+

Components outside normal ranges:

100th day (from January 1, 2010)
24 months (from January 1, 2010)

SELECT DATE_FROM_PARTS(2010, 1, 100), DATE_FROM_PARTS(2010, 1 + 24, 1);
+-------------------------------+----------------------------------+
| DATE_FROM_PARTS(2010, 1, 100) | DATE_FROM_PARTS(2010, 1 + 24, 1) |
|-------------------------------+----------------------------------|
| 2010-04-10                    | 2012-01-01                       |
+-------------------------------+----------------------------------+

Components with zero or negative numbers:

SELECT DATE_FROM_PARTS(2004, 1, 1),   -- January 1, 2004, as expected.
       DATE_FROM_PARTS(2004, 0, 1),   -- This is one month prior to DATE_FROM_PARTS(2004, 1, 1), so it's December 1, 2003.
                                      -- This is NOT a synonym for January 1, 2004.
       DATE_FROM_PARTS(2004, -1, 1)   -- This is two months (not one month) before DATE_FROM_PARTS(2004, 1, 1), so it's November 1, 2003.
       ;
+-----------------------------+-----------------------------+------------------------------+
| DATE_FROM_PARTS(2004, 1, 1) | DATE_FROM_PARTS(2004, 0, 1) | DATE_FROM_PARTS(2004, -1, 1) |
|-----------------------------+-----------------------------+------------------------------|
| 2004-01-01                  | 2003-12-01                  | 2003-11-01                   |
+-----------------------------+-----------------------------+------------------------------+

SELECT DATE_FROM_PARTS(2004, 2, 1),   -- February 1, 2004, as expected.
       DATE_FROM_PARTS(2004, 2, 0),   -- This is one day prior to DATE_FROM_PARTS(2004, 2, 1), so it's January 31, 2004.
       DATE_FROM_PARTS(2004, 2, -1);  -- Two days prior to DATE_FROM_PARTS(2004, 2, 1) so it's January 30, 2004.
+-----------------------------+-----------------------------+------------------------------+
| DATE_FROM_PARTS(2004, 2, 1) | DATE_FROM_PARTS(2004, 2, 0) | DATE_FROM_PARTS(2004, 2, -1) |
|-----------------------------+-----------------------------+------------------------------|
| 2004-02-01                  | 2004-01-31                  | 2004-01-30                   |
+-----------------------------+-----------------------------+------------------------------+

SELECT DATE_FROM_PARTS(2004, -1, -1);  -- Two months and two days prior to DATE_FROM_PARTS(2004, 1, 1), so it's October 30, 2003.
+-------------------------------+
| DATE_FROM_PARTS(2004, -1, -1) |
|-------------------------------|
| 2003-10-30                    |
+-------------------------------+