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declare @d as datetime set @d = datefromparts(2020,10,20) select @d 你要看的那一天 -- 設定你要抓的那一天，比如2020/10/20 set @d = dateadd(month,-6,@d) --減6個月 select datefromparts(year(@d),month(@d),1) 半年前的第一天 -- 用datefromparts串，最後一個參數就是1，沒有懸念 -- 六個月前的最後一天，就是六個月前的第一天加1個月再減1天 set @d = dateadd(month,1,@d) -- 絕不會出現大月小月閏年非閏年的麻煩 select dateadd(day,-1,datefromparts(year(@d),month(@d),1)) 半年前的最後一天
你要看的那一天
2020-10-20 00:00:00.000
半年前的第一天
2020-04-01
半年前的最後一天
2020-04-30