删除部分字段重复数据

[jlds0123]

表 T1

id(主键) A B C D E
1 aa dd vv ni hao
2 cc ff gg ma neng
3 kk dd vv liao ren


T1中B,C字段第一条和第三条有重复，如何删除保留一条

[CN_SQL]

delete a
from t1 a
where exists(
  select *
  from t1
  where b = a.b
     and c = a.c
     and id > a.id)

[dawugui]

delete from t1 where id not in (select max(id) from t1 group by b ,c)

[dawugui]

delete from t1 where id not in (select max(id) from t1 group by b ,c)
delete from t1 where id not in (select min(id) from t1 group by b ,c)

[dawugui]

--其他请参见:

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?谢谢!
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 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)

比方说在A表中存在一个字段“name”，而且不同记录之间的“name”值有可能会相同，
现在就是需要查询出在该表中的各记录之间，“name”值存在重复的项；
Select Name,Count(*) From A Group By Name Having Count(*) > 1

如果还查性别也相同大则如下:
Select Name,sex,Count(*) From A Group By Name,sex Having Count(*) > 1

[bwu851]

delete X
from T1 X
inner join T1 Y on X.B = Y.B and X.C = Y.C
where X.id > Y.id

没经测试....LZ自己测试一下吧.