sql查询重复记录、删除重复记录具体方法

sql查询重复记录、删除重复记录具体方法

本篇文章重点为大家讲解一下sql查询重复记录、删除重复记录具体方法,有需要的小伙伴可以参考一下。

查找所有重复标题的记录:

代码语言:javascript代码运行次数:0运行复制SELECT *

FROM t_info a

WHERE ((SELECT COUNT(*)

FROM t_info

WHERE Title = a.Title) > 1)

ORDER BY Title DESC一、查找重复记录

1.查找全部重复记录

Select * From 表 Where 重复字段 In (Select 重复字段 From 表 Group By 重复字段 Having Count(*)>1)

2.过滤重复记录(只显示一条)

Select * From HZT Where ID In (Select Max(ID) From HZT Group By Title)

注:此处显示ID最大一条记录

二、删除重复记录

1.删除全部重复记录(慎用)

Delete 表 Where 重复字段 In (Select 重复字段 From 表 Group By 重复字段 Having Count(*)>1)

2.保留一条记录

Delete HZT Where ID Not In (Select Max(ID) From HZT Group By Title)

注:此处保留ID最大一条记录

删除多余的重复记录

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

代码语言:javascript代码运行次数:0运行复制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

代码语言:javascript代码运行次数:0运行复制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)

代码语言:javascript代码运行次数:0运行复制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

代码语言:javascript代码运行次数:0运行复制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

代码语言:javascript代码运行次数:0运行复制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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