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