如何在 MSSQL 中获取最近 6 周的开始日期和结束日期

Posted 2023-05-09

【中文标题】如何在 MSSQL 中获取最近 6 周的开始日期和结束日期

【英文标题】：how to get last 6 week start date and end date in MSSQL

【发布时间】：2021-02-18 08:05:22

【问题描述】：

例如，今天是 2021 年 2 月 18 日，那么开始日期是 2021 年 2 月 14 日，结束日期是 2021 年 2 月 20 日。

过去 3 周的这些方式将是：

week	start date	End Date
Week 1	14 Feb 2021	20 Feb 2021
week 2	7 Feb 2021	13 Feb 2021
week 3	31 Jan 2021	6 Feb 2021

第 1 周是当前周，第 2 周是第 1 周的前一周，依此类推

我已经尝试了以下脚本：

select cast(DATEADD(dd, -(DATEPART(dw, getdate())-1), getdate()) as date) [Week1 start]

select cast(DATEADD(dd, 7-(DATEPART(dw, getdate())), getdate()) as date) [Week1 End]

select cast(DATEADD(dd, -8-(DATEPART(dw, getdate())-2), getdate()) as date) [Week2 start]

select cast(DATEADD(dd, -14-(DATEPART(dw, getdate())-2), getdate()) as date) [Week2 END]

显示错误的输出，可以通过指出我出错的地方来帮助我，或者替代获取最近 6 周的开始和结束日期

【参考方案1】：

尝试将当前周开始/结束存储在变量中，然后使用DATEADD 计算前几周：

declare @weekStart date = cast(DATEADD(dd, -(DATEPART(dw, getdate())-1), getdate()) as date)
declare @weekEnd date = cast(DATEADD(dd, 7-(DATEPART(dw, getdate())), getdate()) as date)

select @weekStart, @weekEnd
union all
select DATEADD(dd, -7, @weekStart), DATEADD(dd, -7, @weekEnd)
union all
select DATEADD(dd, -7 * 2, @weekStart), DATEADD(dd, -7  * 2, @weekEnd)

Demo here

【参考方案2】：

您也可以使用递归 CTE 解决此任务：

WITH cte

AS
(
     SELECT cast(DATEADD(dd, -(DATEPART(dw, getdate())-1), getdate()) as date) [Week1 start], cast(DATEADD(dd, 7-(DATEPART(dw, getdate())), getdate()) as date) [Week1 End]

     UNION ALL  
      SELECT cast(DATEADD(dd, -7-(DATEPART(dw, [Week1 start])-1), [Week1 start]) as date) [Week1 start], cast(DATEADD(dd, -1-(DATEPART(dw, [Week1 End])-1), [Week1 End]) as date) [Week1 End]

     FROM cte
     WHERE [Week1 start]>'2021-01-10'
)
     SELECT * FROM cte 

【参考方案3】：

这是你要找的吗？

select cast(DATEADD(dd, -(DATEPART(dw, getdate())-1), getdate()) as date) [Week1 start]
select cast(DATEADD(dd, 7-(DATEPART(dw, getdate())), getdate()) as date) [Week1 End]
select cast(DATEADD(dd, -8-(DATEPART(dw, getdate())-2), getdate()) as date) [Week2 start]
select cast(DATEADD(dd, -(DATEPART(dw, getdate())), getdate()) as date) [Week2 END]
select cast(DATEADD(dd, -15-(DATEPART(dw, getdate())-2), getdate()) as date) [Week3 start]
select cast(DATEADD(dd, -7-(DATEPART(dw, getdate())), getdate()) as date) [Week3 END]