Function to calculate the number of working weekdays Merged

Looking for a simple way to calculate the number of working weekdays. 

DateDiff("weekday",[ORDER DATE],[DELIVERY DATE]) In Spotfire, the closest I got is this reference page, with an absurdly long statement
http://tibcoanalytics.com/spotfire/archive/totw/2010-01-23.html
((((Integer(((Integer(DateDiff("day",[ORDER DATE],[DELIVERY DATE]) / 7) * 5) + DayOfWeek([DELIVERY DATE])) - DayOfWeek([ORDER DATE])) + (if((integer(DayOfWeek([ORDER DATE])))>(integer(DayOfWeek([DELIVERY DATE]))),5,0))) - (if((integer(DayOfWeek([DELIVERY DATE])))=(6),1,0))) + (if((integer(DayOfWeek([DELIVERY DATE])))<>(0),1,0))) + (if((integer(DayOfWeek([DELIVERY DATE])))=(0),1,0))) - (if((integer(DayOfWeek([ORDER DATE])))=(0),1,0))