DAY

The DAY function returns the day part of a value.

DAY(expression)

expression

An expression that returns a value of one of the following built-in data types: a date, a timestamp, a character string, a graphic string, or a numeric data type.

If expression is a character or graphic string, its value must be a valid string representation of a date or timestamp. For the valid formats of string representations of dates and timestamps, see String representations of datetime values.
If expression is a number, it must be a date duration or timestamp duration. For the valid formats of datetime durations, see Datetime operands and durations.

The result of the function is a large integer. If the argument can be null, the result can be null; if the argument is null, the result is the null value.

The other rules depend on the data type of the argument:

If the argument is a date, timestamp, or valid character-string representation of a date or timestamp:
The result is the day part of the value, which is an integer between 1 and 31.
If the argument is a date duration or timestamp duration:
The result is the day part of the value, which is an integer between -99 and 99. A nonzero result has the same sign as the argument.

Examples

Using the PROJECT table, set the host variable END_DAY (SMALLINT) to the day that the WELD LINE PLANNING project (PROJNAME) is scheduled to stop (PRENDATE).
```
SELECT DAY(PRENDATE)
  INTO :END_DAY
  FROM PROJECT
  WHERE PROJNAME = 'WELD LINE PLANNING'
```
Results in END_DAY being set to 15.

Return the day part of the difference between two dates:

  SELECT DAY( DATE('2000-03-15') - DATE('1999-12-31') )
    FROM SYSIBM.SYSDUMMY1

Results in the value 15.