Count work days between two dates

Question

How can I calculate the number of work days between two dates in SQL Server?

Monday to Friday and it must be T-SQL.

Answer 1

Create Function dbo.DateDiff_WeekDays 
(
@StartDate  DateTime,
@EndDate    DateTime
)
Returns Int
As

Begin   

Declare @Result Int = 0

While   @StartDate <= @EndDate
Begin 
    If DateName(DW, @StartDate) not in ('Saturday','Sunday')
        Begin
            Set @Result = @Result +1
        End
        Set @StartDate = DateAdd(Day, +1, @StartDate)
End

Return @Result

End