SQL如何通过当前日期获取上周一日期【转】

--当前时间 
select getdate()
--当前时间周的起始日期（以周一为例）
select DATEADD(week,DATEDIFF(week,0,getdate()),0)
--上周起始：
select dateadd(week,-1,DATEADD(week,DATEDIFF(week,0,getdate()),0))
--上上周起始：
select dateadd(week,-2,DATEADD(week,DATEDIFF(week,0,getdate()),0))
--上上上周起始：s
elect dateadd(week,-3,DATEADD(week,DATEDIFF(week,0,getdate()),0))