sql-去重

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)
 

oracle多列去重cs_smcs_pt表mc、zbwzx去重
delete from cs_smcs_pt 
WHERE mc IN (SELECT mc FROM cs_smcs_pt GROUP BY mc HAVING COUNT(mc) > 1)
      and zbwzx in (SELECT zbwzx FROM cs_smcs_pt GROUP BY zbwzx HAVING COUNT(zbwzx) > 1)
      AND ROWID NOT IN (SELECT MIN(ROWID) FROM cs_smcs_pt GROUP BY mc HAVING COUNT(*) > 1)
      AND ROWID NOT IN (SELECT MIN(ROWID) FROM cs_smcs_pt GROUP BY zbwzx HAVING COUNT(*) > 1)
;
select * from  bzdzpt b where b.dzmc in(
    select t.dzmc from(
        select a.dzmc,count(a.dzmc)
        from bzdz_pt a
        group by a.dzmc
        having count(a.dzmc) > 2
    )t 
)