group up 碰到的问题?

[haoguozhong]

如何把按照字段A group by,同时得到第一条记录所对应字段B,字段C,字段D

如:
id A B C
1 cc 125 255
2 cc 152 254
3 ff 125 555
4 ff 123 ddd
5 cc 2344 111

得到:
id A B C
1 cc 125 255
3 ff 125 555

[xiaoxiangqing]

--方法一:
select * from tablename where id in(select min(id) from tablename group by a)
--方法二:
select a.* from tablename a join (select min(id) id from tablename group by a)b
on a.id=b.id

[Qihua_wu]

select * from tablename where id in(select min(id) from tablename group by a)

select a.* from tablename a join (select min(id) id from tablename group by a)b
on a.id=b.id

select *
from tablename a
where not exists(select 1 from tablename where a.id>id and a.a=a)

[dazhu2]

----建表

create table table1(ID1 int,A varchar(8),B varchar(8),C varchar(8))
Insert into table1
select 1,'cc','125','255'
union all select 2,'cc','152','254'
union all select 3,'ff','125','555'
union all select 4,'ff','123','ddd'
union all select 5,'cc','2344','111'




----查询
select * from table1 where ID1 IN (Select min(ID1) FROM table1 group by [A])



-----删除
drop table t1



-

[Softlee81307]

select *
from tablename k
where id in (select min(id) from tablename where a=k.a group by a)

[xluzhong]

select *
from tablename
where id in (select min(id) from tablename group by a)

[xluzhong]

select *
from tablename a
where not exists(select 1 from tablename where a.id>id and a.a=a)