错误的周数使用DATEPART在SQL Server中 [英] Wrong week number using DATEPART in SQL Server

问题描述

我有这个问题，

select datepart(ww, '20100208')

作为结果 第7周 返回。 > 08.02.2010 应该是 第6周 根据 ISO 8601 规格！

is returning as result week 7 in SQL Server 2000. But 08.02.2010 should be week 6 according to the ISO 8601 specification! This is causing problems in delivery week calculations.

如何根据ISO 8601获取星期数值？

推荐答案

您可以非常容易地在SQL 2008中执行此操作，因为它现在支持 isoww 作为第一个datepart参数。但是，这不是SQL 2000（或2005）。 此中的功能文章将在SQL 2000/2005中为您做。

You can do this within SQL 2008 very easily as it now supports isoww as the first datepart argument. However, this wasn't in SQL 2000 (or 2005). There is a function in this article which will do it for you in SQL 2000/2005.

如果博客脱机，这里是功能。

In case the blog goes offline, here is the function. Go to the post to learn more about ISO and non-ISO weeks.

CREATE FUNCTION ISOweek  (@DATE datetime)
RETURNS int
AS
BEGIN
   DECLARE @ISOweek int
   SET @ISOweek= DATEPART(wk,@DATE)+1
      -DATEPART(wk,CAST(DATEPART(yy,@DATE) as CHAR(4))+'0104')
   --Special cases: Jan 1-3 may belong to the previous year
   IF (@ISOweek=0) 
      SET @ISOweek=dbo.ISOweek(CAST(DATEPART(yy,@DATE)-1 
         AS CHAR(4))+'12'+ CAST(24+DATEPART(DAY,@DATE) AS CHAR(2)))+1
   --Special case: Dec 29-31 may belong to the next year
   IF ((DATEPART(mm,@DATE)=12) AND 
      ((DATEPART(dd,@DATE)-DATEPART(dw,@DATE))>= 28))
      SET @ISOweek=1
   RETURN(@ISOweek)
END

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