SQL语句删除表中重复字段

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)
 
比方说在A表中存在一个字段“name”,而且不同记录之间的“name”值有可能会相同,
 现在就是需要查询出在该表中的各记录之间,“name”值存在重复的项;
 Select Name,Count(*) From A Group By Name Having Count(*) > 1 

  

posted @ 2012-03-27 13:25  cyjch  阅读(2168)  评论(0编辑  收藏  举报