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MySQL刪除重復記錄的方法

數(shù)據(jù)庫 MySQL
如果出現(xiàn)重復記錄,就需要進行刪除操作,下面為您介紹了幾種MySQL刪除重復記錄的方法,希望對您能夠有所幫助。

MySQL刪除重復記錄是我們經(jīng)常用到的操作,下面為您介紹了5種MySQL刪除重復記錄的方法,如果您感興趣的話,不妨一看。

1、查找表中多余的重復記錄,重復記錄是根據(jù)單個字段(peopleId)來判斷
select * from people
where peopleId in (select  peopleId  from  people  group  by  peopleId  having  count(peopleId) > 1)

2、刪除表中多余的重復記錄,重復記錄是根據(jù)單個字段(peopleId)來判斷,只留有rowid最小的記錄
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、查找表中多余的重復記錄(多個字段)
select * from vitae a
where (a.peopleId,a.seq) in  (select peopleId,seq from vitae group by peopleId,seq  having count(*) > 1)

4、刪除表中多余的重復記錄(多個字段),只留有rowid最小的記錄
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、查找表中多余的重復記錄(多個字段),不包含rowid最小的記錄
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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責任編輯:段燃 來源: 互聯(lián)網(wǎng)
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