Question

包含60 000 000条记录的大型SQL 2008表，我遇到重复行的问题。

这个命令让我复制了我的副本 http://support.microsoft.com/kb/139444

SELECT     id, sa_trvalue,  COUNT(*) AS tot  
FROM         msanal   
GROUP BY id, sa_trvalue  
HAVING      (COUNT(*) > 1)

但是当我按照步骤（INTO和DISTINCT）进行操作时，我没有足够的内存来完成操作。

Answer 1

您可以尝试这种可能需要更少内存的方法：

WITH CTE AS
(
    SELECT  id, sa_trvalue, 
            rn = ROW_NUMBER() OVER (PARTITION BY id, sa_trvalue ORDER BY id ASC)
    FROM    msanal   
)
DELETE FROM CTE WHERE rn > 1

公用表表达式的优点还在于您可以轻松修改它以查看要删除的内容。因此，您只需将DELETE更改为SELECT *。

Answer 2

delete msanal from msanal m1
where exists
(select null from msanal m2
where m2.sa_trvalue = m1.sa_trvalue and m2.id <> m1.id)

大型SQL数据库删除重复的行

2 个答案: