工作日查询（一段日期内的工作日天数查询）

/*
--马万前
--2010-1-15
--查询工作日内的工作天数
*/
Create Function dbo.f_WorkDay
(
 @date_Begin datetime,
 @date_end datetime
)
returns int
as
begin
 declare @weeks int
 declare @workday int
 select @weeks = (datediff(day,@date_Begin,@date_End)+1)/7,
  @workday= @weeks * 5,
  @date_Begin = dateadd(day,@weeks * 7,@date_begin)
while @date_Begin<=@date_End
begin
 select @workday= case
   when (@@datefirst + datepart(weekday,@date_Begin)-1)%7 between 1 and 5
   then @workday +1
   else
    @workday
   end,
  @date_Begin = @date_Begin + 1
 end
return (@workday)
end
go

select dbo.f_workday('2010-1-10','2010-1-18')