-- sql server 獲取上週幾和本週幾

-- @@DATEFIRST 每週以周幾開始，週一是 1 ，週日是 7 ，有些機器預設是7，有些機器預設是1
SELECT @@DATEFIRST
-- 修改 @@DATEFIRST 的值
SET DATEFIRST 7
-- 查詢當前每週是以周幾開始，今天是一週的第幾天
SELECT @@DATEFIRST as 'startday', DATEPART(dw,GETDATE()) as 'weekday'

-- 通過 WEEKDAY 和 @@DATEFIRST 聯合計算，抹平 @@DATEFIRST 設定的差異

-- 上週
SELECT
 
 
 CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) - 6, GETDATE()) ) as '上週一'
,CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) - 5, GETDATE()) ) as '上週二'
,CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) - 4, GETDATE()) ) as
 
 '上週三'
,CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) - 3, GETDATE()) ) as '上週四'
,CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) - 2, GETDATE()) ) as '上週五'
,CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) - 1, GETDATE
 
()) ) as '上週六'
,CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) - 0, GETDATE()) ) as '上週日'

-- 本週
SELECT 
 CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) + 1, GETDATE()) ) as '本週一'
,CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) + 2, GETDATE()) ) as '本週二'
,CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) + 3, GETDATE()) ) as '本週三'
,CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) + 4, GETDATE()) ) as '本週四'
,CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) + 5, GETDATE()) ) as '本週五'
,CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) + 6, GETDATE()) ) as '本週六'
,CONVERT(DATE, DATEADD(dd, -DATEPART (WEEKDAY ,GETDATE() + @@DATEFIRST - 1) + 7, GETDATE()) ) as '本週日'