以下代码返回什么？ sql server 2012

Question

我正在挖掘一些代码，我不是sql的专家。有谁可以告诉我，以下内容会返回什么？

select DATEADD(day, DATEPART(weekday, GETDATE()) * - 1, GETDATE())

Answer 1

以外行人的话说，这会返回“上周六”。如果“今天”是星期六，它仍然会在星期六之前返回。

-- This will make it very apparent
-- Please note that the DatePart() function is language/settings dependant. So while on one server set up it may return "last Saturday", on others it may return "last Sunday"
select DATEADD(day, DATEPART(weekday, '11/01/2013') * -1, '11/01/2013')
select DATEADD(day, DATEPART(weekday, '11/02/2013') * -1, '11/02/2013')
select DATEADD(day, DATEPART(weekday, '11/03/2013') * -1, '11/03/2013')
select DATEADD(day, DATEPART(weekday, '11/04/2013') * -1, '11/04/2013')
select DATEADD(day, DATEPART(weekday, '11/05/2013') * -1, '11/05/2013')
select DATEADD(day, DATEPART(weekday, '11/06/2013') * -1, '11/06/2013')
select DATEADD(day, DATEPART(weekday, '11/07/2013') * -1, '11/07/2013')

Answer 2

DATEPART(weekday, GETDATE())

每周回复你。

• sunday = 1

• 星期一= 2

• 等...

然后：

select DATEADD(day, DATEPART(weekday, GETDATE()) * - 1, GETDATE())

示例周三= 4

将（4天* -1）添加到今天=今天 - 4天