ORACLE PL-SQL - Business days calculation

There are many versions of this out there if you look around.

Holidays are the tricky part.  Do you currently have a table that contains the valid holidays?  If not, you're probably going to need one.

This "quick and dirty" approach can efficiently get you close to the number of weekdays between any two dates, expecially if they are at least a week apart:

select round((ending_date - starting_date) * 5 /7,0) "Weekdays" from dual;

Substitute actual column names or "to_date('a literal','[format mask')" for the "starting_date" and "ending_date" variables.

As sligthwv indicated, you will need a custom table to keep of your holidays, since these tend to be different for each organization.  You can add a sub-query from that custom holiday table something like this:

select count(*) from my_holidays
where holiday_date between starting_date and ending_date;

Then subtract this from the result of the other query I suggested, or the one slightwv suggested (which is more accurate, but may be slower).

What about this one here?! I'd give it a shot ;-)

http://www.dba-oracle.com/t_list_of_public_holidays.htm

My workmate mentioned we have a function that exists. How do I call a function with a PL/SQL query? He said it's something like this: sf_workdays (StartDate in Date, EndDate in Date).
Tried and it's not working.

why the B?

a penalty grade isn't appropriate here

why the B?

a penalty grade isn't appropriate here

Yes, why the "B"?!

Maybe this guide will help: http://support.experts-exchange.com/customer/portal/articles/481419