SQL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

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)    删除重复数据保留id最大那条 select b.id,b.username from test b where b.id not in (select max(t.id) as id from test t having count(t.username) > 1 group by t.username) and b.username in (select t.username from test t having count(t.username) > 1 group by t.username); 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)    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