数据库操作

[lxfei73]

如何在SQL中删除重复的记录，是用什么命令

[csshan]

有很多方法.
简单明了的:

--原始的A ,
--tempTable 
select distinct * into tempTable from A
drop table A
select * into A from tempTable 

还可以用按分组方式来做

[jwdream2008]

--功能概述:删除重复记录
--做成时间:2008/10/31

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 
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 

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

[xiaojin0710]

我每次都是一行一行的删，帮楼主顶

[xiaojin0710]

我每次都是一行一行的删，帮楼主顶

[wuyq11]

http://www.cnblogs.com/dalink/articles/220654.html