码农公寓

在几千条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复的呢?谢谢!
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
deletefrom people
where peopleId  in (select  peopleId  from people  group  by  peopleId  having  count(peopleId) >1)
and rowid notin (selectmin(rowid) from  people  groupby peopleId  havingcount(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 groupby peopleId,seq  havingcount(*) >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
deletefrom vitae a
where (a.peopleId,a.seq) in  (select peopleId,seq from vitae groupby peopleId,seq havingcount(*) >1)
and rowid notin (selectmin(rowid) from vitae groupby peopleId,seq havingcount(*)>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 groupby peopleId,seq havingcount(*) >1)
and rowid notin (selectmin(rowid) from vitae groupby peopleId,seq havingcount(*)>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 GroupBy Name HavingCount(*) >1

如果还查性别也相同大则如下:
Select Name,sex,Count(*) From A GroupBy Name,sex HavingCount(*) >1