SQL to return the number of working days between 2 passed in dates

Question

I need to write an sql query that returns the number of Working days (Monday - Friday) between two given dates.

I was wondering what would be the most efficient way

Answer 1

an easy way to calculate to number of weekdays between 2 dates is :

SELECT
date1,
date2,
((date2-date1)-2*FLOOR((date2-date1)/7)-DECODE(SIGN(TO_CHAR(date2,'D')-
    TO_CHAR(date1,'D')),-1,2,0)+DECODE(TO_CHAR(date1,'D'),7,1,0)-
    DECODE(TO_CHAR(date2,'D'),7,1,0))*24 as WorkDays
FROM
  tablename
ORDER BY date1,date2