mysql having 去重复,having count删除重复数据只保留一条

数据只保留一条"/>

mysql having 去重复,having count删除重复数据只保留一条

having count删除重复数据只保留一条 用SQL语句,删除掉重复项只保留一条 www.2cto 在几千条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复的呢 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 wher

having count删除重复数据只保留一条

用SQL语句,删除掉重复项只保留一条

www.2cto

在几千条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复的呢

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)

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 peopleName in (select peopleName from people group by peopleName having count(peopleName) > 1)

and peopleId not in (select min(peopleId) from people group by peopleName having count(peopleName)>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 h