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 x
(
    @StartDate DATETIME,
    @EndDate DATETIME
)
RETURNS INT
AS
BEGIN
    DECLARE @Teller INT

    SET @StartDate = DATEADD(dd,1,@StartDate)

    SET @Teller = 0
    IF DATEDIFF(dd,@StartDate,@EndDate) <= 0
    BEGIN
        SET @Teller = 0 
    END
    ELSE
    BEGIN
        WHILE
            DATEDIFF(dd,@StartDate,@EndDate) >= 0
        BEGIN
            IF DATEPART(dw,@StartDate) < 6
            BEGIN
                SET @Teller = @Teller + 1
            END
            SET @StartDate = DATEADD(dd,1,@StartDate)
        END
    END
    RETURN @Teller
END