一.查找重复记录
1.查找所有重复记录
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)
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SELECT *
FROM?CompanyEmail?c
WHERE ((SELECT COUNT(*)
FROM?CompanyEmail??
WHERE?Email= a.Email) > 1)
ORDER BY?Email?DESC
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2.过滤重复记录(只显示一条ID最大的)
Select * From?CompanyEmail??Where ID In (Select Max(ID) From?CompanyEmail??Group By?Email)
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二.删除重复记录
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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)
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2.保留一条,删除其他重复记录
Delete?CompanyEmail?Where ID Not In (Select Max(ID) From?CompanyEmail?Group By?Email)
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3. 删除多字段相同的重复记录，保留一条
delete CompanyEmail where ID not in (select max(ID) from CompanyEmail group by Email, Company)
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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)
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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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