Question

我创建了一个查询

DELETE 
FROM   [dbo].[AKA$Item Stock Changes Log] AS gone,SELECT t.[Item No_] , 
       t.[Last Date Modified] , 
       t.[Location Code] 
FROM   ( 
              SELECT [Item No_] , 
                     [Last Date Modified] , 
                     [Location Code] , 
                     [Activity] 
              FROM   [dbo].[AKA$Item Stock Changes Log]) AS t 
WHERE  t.[Last Date Modified]< 
       ( 
              SELECT Max(b.[Last Date Modified]) 
              FROM   ( 
                            SELECT [Item No_] , 
                                   [Last Date Modified] , 
                                   [Location Code] , 
                                   [Activity] 
                            FROM   [dbo].[AKA$Item Stock Changes Log]) AS b 
              WHERE  b.[Location Code]=t.[Location Code] 
              AND    b.[Item No_]=t.[Item No_]) as needed 
WHERE  gone.[Item No_]=needed.[Item No_] 
AND    gone.[Location Code]=needed.[Location Code] 
AND    gone.[Last Date Modified]=needed.[Last Date Modified]

名为needed的子查询包含我要删除的行。但查询不起作用，我不知道如何处理。

以下是一些示例数据。我的主要目标是查询获取[Item No_]和[Location Code]相等的行并删除除最新

之外的所有行

Item No_             Last Date Modified      Location Code
-------------------- ----------------------- --------------------
0015672              2017-12-28 14:28:51.847 JV                  should stay
0015672              2017-12-28 14:28:51.847 KN                  should stay
0015672              2017-12-28 14:28:48.990 JV                  delete
0015672              2017-12-28 14:28:48.990 KN                  delete
0015672              2017-12-28 14:28:30.547 JV                  delete
0015672              2017-12-28 14:28:30.547 KN                  delete
0036539              2017-12-28 14:27:54.190 KN                  
0036539              2017-12-28 14:27:54.190 JV                  
0044623              2017-12-28 14:27:54.190 KN                  
0044623              2017-12-28 14:27:54.190 JV                  
0036539              2017-12-28 14:27:48.850 KN                  
0036539              2017-12-28 14:27:48.850 JV

Answer 1

您可以CTE使用ROW_NUMBER()。这将从源表中删除记录。

;with cte as (
select 
    *
    ,RN = row_number() over (partition by [Item No_], [Location Code] order by [Last Date Modified] desc)
from
    YourTable)

delete from cte where RN <> 1

从表中删除行

1 个答案: