Calculate difference between 2 dates in SQL, excluding weekend days

Question

I would like to build an SQL query which calculates the difference between 2 dates, without counting the week-end days in the result.

Is there any way to format the dates to obtain this result ? For example for Oracle database :

select sysdate - creation_dttm from the_table

Answer 1

You should try with a function :

CREATE FUNCTION TOTAL_WEEKDAYS(date1 DATE, date2 DATE)
RETURNS INT
RETURN ABS(DATEDIFF(date2, date1)) + 1
     - ABS(DATEDIFF(ADDDATE(date2, INTERVAL 1 - DAYOFWEEK(date2) DAY),
                    ADDDATE(date1, INTERVAL 1 - DAYOFWEEK(date1) DAY))) / 7 * 2
     - (DAYOFWEEK(IF(date1 < date2, date1, date2)) = 1)
     - (DAYOFWEEK(IF(date1 > date2, date1, date2)) = 7);

Test :

SELECT TOTAL_WEEKDAYS('2013-08-03', '2013-08-21') weekdays1,
       TOTAL_WEEKDAYS('2013-08-21', '2013-08-03') weekdays2;

Result :

| WEEKDAYS1 | WEEKDAYS2 |
-------------------------
|        13 |        13 |