查询表中重复的记录数据sql

1、一张表中有id和name 两个字段,查询出name重复的所有数据,现在列下:

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

2、查询出所有数据进行分组之后,和重复数据的重复次数的查询数据,先列下:

select  count(username) as ‘重复次数’,username from xxxxxx group by username  having count(username)>1 order by username desc

3、查询及删除重复记录的方法大全

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)

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