前言:
此时咱们对“sql查询去重”大概比较讲究,同学们都需要知道一些“sql查询去重”的相关文章。那么小编也在网摘上收集了一些有关“sql查询去重””的相关资讯,希望我们能喜欢,你们快快来学习一下吧!查找所有重复标题的记录:
SELECT *FROM t_info aWHERE ((SELECT COUNT(*)FROM t_infoWHERE 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
select * from peoplewhere 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 peoplewhere 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 awhere (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 awhere (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 awhere (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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