DAYS

The DAYS function returns an integer representation of a date.


>>-DAYS--(--expression--)--------------------------------------><

expression: An expression that returns a value of one of the following built-in data types: a date, a timestamp, a character string, or a graphic string.
If expression is a character or graphic string, it must not be a CLOB or DBCLOB, and 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.

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 result is 1 more than the number of days from January 1, 0001 to D, where D is the date that would occur if the DATE function were applied to the argument.

Examples

Using the PROJECT table, set the host variable EDUCATION_DAYS (INTEGER) to the number of elapsed days (PRENDATE - PRSTDATE) estimated for the project (PROJNO) ‘IF2000'.
```
  SELECT DAYS(PRENDATE) - DAYS(PRSTDATE)
    INTO :EDUCATION_DAYS
    FROM PROJECT
    WHERE PROJNO = 'IF2000'
```
Results in EDUCATION_DAYS being set to 396.
Using the PROJECT table, set the host variable TOTAL_DAYS (INTEGER) to the sum of elapsed days (PRENDATE - PRSTDATE) estimated for all projects in department (DEPTNO) ‘E21'.
```
SELECT SUM(DAYS(PRENDATE) - DAYS(PRSTDATE))
  INTO :TOTAL_DAYS
  FROM PROJECT
  WHERE DEPTNO = 'E21'
```
Results in TOTAL_DAYS being set to 1584.