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mysql 去重复内容的办法

//查找单个字段重复的

select  username  from  passport_members  group  by  username  having  count( username ) > 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:查找重复

select * from tablename where id in ( select id from tablename group by id having count(id) > 1) 

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