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oracle删除同一张表的重复记录

Posted on 2012-06-20 10:25  my_house_station  阅读(628)  评论(0编辑  收藏  举报

1、查找表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断
select * from people
where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)

2、删除表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断,只留有rowid最小的记录
delete from people 
where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)
and rowid not in (select min(rowid) from people group by peopleId having count(peopleId )>1)

3、查找表中多余的重复记录(多个字段) 
select * from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,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 vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
and rowid not in (select min(rowid) from vitae group by peopleId,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 vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)


关键看什么字段相同算重复,如果是arrearmain_id、reladdr、addrsourcetype的话,那这样写是最高效的,因为用了rowid:
delete from cncc_customeraddr_tab t
 where t.rowid > (select min(x.rowid)
  from cncc_customeraddr_tab x
  where x.arrearmain_id = t.arrearmain_id
  and x.reladdr = t.reladdr
  and x.addrsourcetype = t.addrsourcetype)
  and t.addrsourcetype = '1300000001'