Question

can i use to_number(to_char()) function in order to exclude all the weekends from a range of dates?

For instance, there are two date columns in my table such as start and finish (in the form of ’06/06/2011 10:00:00 am’), and i want to estimate the duration of finish-start excluding Saturdays and Sundays.

Answer 1

If I understand you right you want to calculate the difference between two dates, but exclude the 2 days of each weekend in the range from the result. Is that correct?

If this is what you want the below code should work with the following assumptions:

• I am assume start and end will not be on weekends.
• I am not validating that end is before start.

Basically its just a matter of working out how many weekends are in the date range. So obviously there’s one weekend per 7 days. Then we just have to check if the range wraps around a weekend, and if so add one more.

FUNCION dateDiff( dt_start DATE, dt_end DATE ) RETURN NUMBER
IS
    raw_diff NUMBER;
    weekends NUMBER;
BEGIN
    raw_diff := dt_end - dt_start;
    weekends := TRUNC( raw_diff / 7 );
    IF( ( dt_start - TRUNC( dt_start, 'DAY' ) )
      > ( dt_end   - TRUNC( dt_end  , 'DAY' ) ) )
    THEN
        weekends := weekends + 1;
    END IF;
    RETURN raw_diff - ( weekends * 2 );
END;