Firstly, you should have two tables:  1. Source table  with the records, and two fields of these records should be two dates that will set the period. 2. A table where you store holidays dates. You should create a datapage on the first table and create a Calculated Field on the "Configure Results Page Fields" screen with the following code: SELECT (DATEDIFF(dd, [@field:Date1], [@field:Date2]) + 1) -(DATEDIFF(wk, [@field:Date1], [@field:Date2])*2) -( SELECT Count(*) FROM Holidays  WH