Number of Weekdays between two dates - Set Based

/*----------------------------------------------------------------------

Supporting Table called Sequence.  This table is useful for a number of things.

*/----------------------------------------------------------------------

CREATE TABLE [Sequence] (
	[SequenceID] [int] IDENTITY (1, 1) NOT NULL ,
	 PRIMARY KEY  CLUSTERED 
	(
		[SequenceID]
	)  ON [PRIMARY] 
) ON [PRIMARY]
GO


declare @SequenceID Int

While isnull(@SequenceID, 0) <=1000

	BEGIN
	
	Insert Sequence default values

	select @SequenceID = @@identity

	END



/*----------------------------------------------------------------------

Function that calculates the number of work days between two dates.
The working days are considered the first and last day of every week

*/----------------------------------------------------------------------


create function UTIL_WorkingDaysDiff(@StartDate datetime, @EndDate datetime)

returns int

as

begin

declare @Count int


--check for null values
if @StartDate is null or @EndDate is null
		goto fEND


---check that dates aren't the same
if convert(varchar(12), @StartDate, 101) = convert(varchar(12), @EndDate, 101)
	BEGIN
		Select @Count = 0
		goto fEND
	END


--check that startdate < endDate
if @StartDate > @EndDate 
		goto fEND


select @Count =
	sum	(
	Case	datepart(weekday, dateadd(dd, SequenceID, @StartDate))
		When 1 	then 0--Sunday
		When 7 	then 0--Saturday
				Else 1
	END
			)
From 	Sequence
where 	SequenceID <= datediff(dd, @StartDate, @EndDate)

fEND:

return @Count

END