sql server:自定義計算固定工作日，雙休日函數

---sql server 
declare @date datetime
set @date='2012-02-03'--getdate()
--本月第一天
SELECT DATEADD(mm, DATEDIFF(mm,0,@date), 0)
--本月最后一天
SELECT dateadd(ms,-3,DATEADD(mm, DATEDIFF(m,0,@date)+1, 0))


---有個月多少天函數
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[GetAMonthHowNumber]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[GetAMonthHowNumber]
GO
CREATE   function  GetAMonthHowNumber
(  
	@date datetime
)
returns int
as
begin
	declare @int int
	select @int=datediff(dd , @date , dateadd(mm, 1, @date))
	return @int
end
GO

--
select [dbo].[GetAMonthHowNumber] (getdate()) AS '月天數'


---計算當月周六，周日有多少天
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[GetAMonthStatSunNumber]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[GetAMonthStatSunNumber]
GO
CREATE   function  GetAMonthStatSunNumber
(  
	@date datetime
)
returns int
as
begin
declare @Sdate datetime ,@Edate datetime

SELECT @Sdate=DATEADD(mm, DATEDIFF(mm,0,@date), 0)
SELECT @Edate=dateadd(ms,-3,DATEADD(mm, DATEDIFF(m,0,@date)+1, 0))
--set @Sdate='2013-05-01'
--set @Edate='2013-05-31'
declare @aa table (strdate datetime)  
declare @i int  
set @i=datediff(day,@Sdate,@Edate)  
while(@i>=0)  
begin  
insert @aa  values (dateadd(day,@i,@Sdate))  
set @i=@i-1  
end  
select @i= count(*)  from @aa where   datepart(weekday,strdate) in (1,7)  --not in (1,7)
return @i
end
go

--
select [dbo].[GetAMonthStatSunNumber] (getdate()) AS '雙休日天數'



--計算當月除周六，周日有多少天，也是有多少工作日
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[GetAMonthWorkDayNumber]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[GetAMonthWorkDayNumber]
GO
CREATE   function  GetAMonthWorkDayNumber
(  
	@date datetime
)
returns int
as
begin
declare @Sdate datetime ,@Edate datetime

SELECT @Sdate=DATEADD(mm, DATEDIFF(mm,0,@date), 0)
SELECT @Edate=dateadd(ms,-3,DATEADD(mm, DATEDIFF(m,0,@date)+1, 0))
--set @Sdate='2013-05-01'
--set @Edate='2013-05-31'
declare @aa table (strdate datetime)  
declare @i int  
set @i=datediff(day,@Sdate,@Edate)  
while(@i>=0)  
begin  
insert @aa  values (dateadd(day,@i,@Sdate))  
set @i=@i-1  
end  
select @i= count(*)  from @aa where   datepart(weekday,strdate) not in (1,7)  --not in (1,7)
return @i
end
go

---
select [dbo].[GetAMonthWorkDayNumber] (getdate()) as '工作日天數'