OracleHaving关键字的使用,删除重复数据但保留一条

Posted 2022-12-06 Jack小强

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 byId 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)