I just wrote a stored function to calculate the working days between two dates. This works

select CountWeekDays('2010-03-07','2010-04-07')

This doesn't work

select CountWeekDays(o.order_date,o.created_date) from orders o;

Any idea how to make this one work ??

function definition

delimiter $$;

CREATE FUNCTION CountWeekDays (sdate VARCHAR(50), edate VARCHAR(50)) RETURNS INT

BEGIN

DECLARE wdays, tdiff, counter, thisday smallint;

DECLARE newdate DATE;

SET newdate := sdate;

SET wdays = 0;

if DATEDIFF(edate, sdate) = 0 THEN RETURN 1; END IF;

if DATEDIFF(edate, sdate) < 0 THEN RETURN 0; END IF;

label1: LOOP

SET thisday = DAYOFWEEK(newdate);

IF thisday BETWEEN 2 AND 6 THEN SET wdays := wdays + 1; END IF;

SET newdate = DATE_ADD(newdate, INTERVAL 1 DAY);

IF DATEDIFF(edate, newdate) < 0 THEN LEAVE label1; END IF;

END LOOP label1;

RETURN wdays;

END