你如何计算两个日期之间的星期数？

Question

你如何计算两个日期之间的星期数？

例如如下

Declare @StartDate as DateTime = "01 Jan 2009"; 
Declare @EndDate as DateTime = "01 June 2009"; 

@StartDate and @EndDate 

Answer 1

使用DateDiff函数。 datediff(ww,@startdate,@enddate)

的WW讲述了要算什么单位你需要的不同功能

http://msdn.microsoft.com/en-us/library/ms189794.aspx

Answer 2

您可以使用下面的函数来retrives本周的两个日期之间：

CREATE FUNCTION [dbo].[fGetWeeksList] 
(
    @StartDate DATETIME 
    ,@EndDate DATETIME 
) 
RETURNS 
TABLE 
AS 
RETURN 
(

SELECT DATEADD(DAY,-(DATEPART(DW,DATEADD(WEEK, x.number, @StartDate))-2),DATEADD(WEEK, x.number, @StartDate)) as [StartDate] 
     ,DATEADD(DAY,-(DATEPART(DW,DATEADD(WEEK, x.number + 1, @StartDate))-1) ,DATEADD(WEEK, x.number + 1, @StartDate)) AS [EndDate] 
FROM master.dbo.spt_values x 
WHERE x.type = 'P' AND x.number <= DATEDIFF(WEEK, @StartDate, DATEADD(WEEK,0,CAST(@EndDate AS DATE)))