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Oracle删除重复数据

2013-04-24 16:13
分类: PL/SQL

Oracle 删除重复数据只留一条,查询及删除重复记录的SQL语句

1、查找表中多余的重复记录,重复记录是根据单个字段(Id)来判断

select * from 表 where Id in (select Id from 表 group by Id having count(Id) > 1)

2、删除表中多余的重复记录,重复记录是根据单个字段(Id)来判断,只留有rowid最小的记录

DELETE from 表 
WHERE (id) IN ( SELECT id FROM 表 GROUP BY id HAVING COUNT(id) > 1) AND ROWID NOT IN (SELECT MIN(ROWID) FROM 表 
GROUP BY id 
HAVING COUNT(*) > 1);

3、查找表中多余的重复记录(多个字段)

select * from 表 a where (a.Id,a.seq) in(select Id,seq from 表 group by Id,seq having count(*) > 1)

4、删除表中多余的重复记录(多个字段),只留有rowid最小的记录

delete from 表 a 
where (a.Id,a.seq) in 
(select Id,seq from 表 group by Id,seq having count(*) > 1) and rowid not in (select min(rowid) from 表 group by Id,seq having count(*)>1)

5、查找表中多余的重复记录(多个字段),不包含rowid最小的记录

select * from 表 a 
where (a.Id,a.seq) in 
(select Id,seq from 表 group by Id,seq having count(*) > 1) and rowid not in (select min(rowid) from 表 group by Id,seq having count(*)>1)

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