I'm with CELKO - use a calendar table, then you can count your Sundays, weekends, Easter Mondays and whatever else you need between two dates - much much easier, and kind on processing too.

For an example calendar, you can check out:

http://www.kimballgroup.com/data-warehouse-and-business-intelligence-resources/data-warehouse-books/booksmdwt/ (go to Chapter 7—Design and Develop the ETL System; date dimension) - Direct Link for DDL and sample data:

http://www.kimballgroup.com/wp-content/uploads/2012/07/Ch07_Date_Dim_2000-2020.xlsx

HTH,

B