Matching Interval With Interval

[Anonymous]

I'm trying to match two date ranges and then count the number of days that overlap from one to another. Both intervals reside in a same table. For example, I'm trying to calculate number of DaysDiscounted:

FromActualDate     ToActualDate     FromDiscountDate     ToDiscountDate     DaysDiscounted

3/24/2013               4/6/2013           4/1/2013                    4/10/2013              6

4/7/2013                 4/20/2013         4/1/2013                    4/10/2013              4

3/24/2013               4/6/2013           4/1/2013                    4/5/2013                5

I could implenet manual logic something like a calculated field like:

=if(ToDiscountDate > ToActualDate, (ToDiscountDate - ToActualDate)+1,(ToActualDate - FromDiscountDate)+1)

but it does not work in all Cases, wondering if QlikView provides more effiecient way, similar to IntervalMatch.

Any suggestions?