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 
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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 having count(*) > 1) 
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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)   
 
6.消除一个字段的左边的第一位： 
 
update tableName set [Title]=Right([Title],(len([Title])-1)) where Title like '村%' 
 
7.消除一个字段的右边的第一位： 
 
update tableName set [Title]=left([Title],(len([Title])-1)) where Title like '%村' 
 
8.假删除表中多余的重复记录（多个字段），不包含rowid最小的记录 
update vitae set ispass=-1 
where peopleId in (select peopleId from vitae group by peopleId 
 

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