在sql Server自定義一個用戶定義星期函數(shù)

更新時間：2012年01月28日 22:39:43 作者：

程序開發(fā)過程中需要做周別統(tǒng)計與顯示報表。在做之前，得先找出所在年份周別的開始日期與結束日期。每年每周的開始與結束日期都不盡相同。為了該功能，在sql Server自定義一個用戶定義星期函數(shù)

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下載地址：SqlFunction_udf_Week.rar
以下內容于20120105更新：
2012年剛到，開發(fā)的軟件使用這個函數(shù)發(fā)現(xiàn)bug。2012年第一周應該是2012-01-01至2012-01-07，但此函數(shù)卻把2012-01-08至2012-01-14當作第一周。

就此bug對此函數(shù)修改如下：

復制代碼代碼如下:

 
SET ANSI_NULLS ON 
GO 
SET QUOTED_IDENTIFIER ON 
GO 
ALTER FUNCTION [dbo].[udf_Week] 
( 
@StartYear INT, 
@EndYear INT 
) 
RETURNS @Week TABLE([WeekId] INT IDENTITY(1,1) PRIMARY KEY,[Year] [INT] NULL,[Week] [INT] NULL,[StartDate] [DATETIME] NULL,[EndDate] [DATETIME] NULL) 
AS 
BEGIN 
DECLARE @YearStartDate DATETIME 
DECLARE @YearEndDate DATETIME 
DECLARE @WeekStartDate DATETIME 
DECLARE @WeekEndDate DATETIME 
DECLARE @Weeks INT 

WHILE @StartYear <= @EndYear 
BEGIN 
SET @YearStartDate = CAST((CAST(@StartYear AS VARCHAR(4)) + '-01-01') AS DATETIME) 
SET @YearEndDate= CAST((CAST(@StartYear AS VARCHAR(4))+ '-12-31') AS DATETIME) 
SET @Weeks = 1 

IF DATEPART(DW,@YearStartDate) > 4 
SET @YearStartDate = DATEADD(DAY,(8 - DATEPART(DW,@YearStartDate)) ,@YearStartDate) 
ELSE 
SET @YearStartDate = DATEADD(DAY,(-(DATEPART(DW,@YearStartDate)-1)),@YearStartDate) 

SET @WeekStartDate = @YearStartDate 
SET @WeekEndDate = DATEADD(DAY,6,@WeekStartDate) 
WHILE DATEDIFF(DAY,@WeekStartDate,@YearEndDate) >= 4 
BEGIN 
INSERT INTO @Week([Year],[Week],[StartDate],[EndDate]) VALUES (@StartYear,@Weeks,@WeekStartDate,@WeekEndDate) 
SET @Weeks = @Weeks + 1 
SET @WeekStartDate = @WeekStartDate + 7 
SET @WeekEndDate = @WeekEndDate + 7 
END 
SET @StartYear = @StartYear + 1 
END 
RETURN 
END 