Question

我正在尝试删除数据库中的重复案例。共有3个字段：ProjectID，ClientID，LastVerified。

我们的某个应用存在问题，并且已创建了多个新的ProjectID。

我想要做的是删除重复项，只留下上次验证的行。例如：

    ProjectID   ClientID    LastVerified
     20773        336106    2016-07-29 01:38:37.450
     20869        336106    2016-08-23 11:19:51.153

在这里，我想保留上次验证的第二行。

我正在使用SQL数据库任何帮助，将不胜感激感谢

Answer 1

你可以这样做：

DELETE X FROM
(
     SELECT *, ROW_NUMBER() OVER (PARTITION BY ClientID ORDER BY LastVerified DESC) R
     FROM @t
) X
WHERE R!=1

Answer 2

如果存在具有相同ClientID的另一行，则删除一行：

delete from tablename t1
where exists (select * from tablename t2
              where t2.ClientID = t1.ClientID
                and t2.LastVerified > t1.LastVerified)

Answer 3

WITH CTE AS(
   SELECT [col1], [col2], [col3], [col4], [col5], [col6], [col7],
       RN = ROW_NUMBER()OVER(PARTITION BY col1 ORDER BY col1)
   FROM dbo.Table1
)
DELETE FROM CTE WHERE RN > 1

Answer 4

这有助于你和max（projectid）帮助找到最后一次验证。所以查询变得简单

DELETE FROM TABLE1 WHERE PROJECTID NOT IN 
(SELECT MAX(PROJECTID) FROM TABLE1 GROUP BY CLIENTID)

基于Lastupdated Date SQL删除重复值

4 个答案: