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对重复的记录使用SQL进行查询和删除等操作

發(fā)布時(shí)間:2025/3/20 数据库 12 豆豆
生活随笔 收集整理的這篇文章主要介紹了 对重复的记录使用SQL进行查询和删除等操作 小編覺(jué)得挺不錯(cuò)的,現(xiàn)在分享給大家,幫大家做個(gè)參考.
1、查找表中多余的重復(fù)記錄,重復(fù)記錄是根據(jù)單個(gè)字段(peopleId)來(lái)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(fù)記錄,重復(fù)記錄是根據(jù)單個(gè)字段(peopleId)來(lái)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(fù)記錄(多個(gè)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(fù)記錄(多個(gè)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(fù)記錄(多個(gè)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)

比方說(shuō)
在A表中存在一個(gè)字段“name”,
而且不同記錄之間的“name”值有可能會(huì)相同,
現(xiàn)在就是需要查詢(xún)出在該表中的各記錄之間,“name”值存在重復(fù)的項(xiàng);
Select Name,Count(*) From A Group By Name Having Count(*) > 1

如果還查性別也相同大則如下:
Select Name,sex,Count(*) From A Group By Name,sex Having Count(*) > 1

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