一个简单SQL问题

[Aylazhang]

table数据如下
[code=BatchFile]A B
－－－－－－－
a 2007-10-30
a 2007-10-31
b 2006-04-01
b 2008-01-01
c 1999-01-02
c 2003-04-05
c 2007-10-02[/code]

我想要得到
[code=BatchFile]a 2007-10-30
b 2006-04-01
c 1999-01-02[/code]

即：对A字段去重，选出的B字段为min(B) ,请问这样的sql怎么写。

[OracleRoob]

select A,min(B) as B
from 表名
group by A

[Aylazhang]

先谢谢。
不过,忘记了一列。
[code=BatchFile]
A D B
－－－－－－－
a a1 2007-10-30
a a2 2007-10-31
b b1 2006-04-01
b b2 2008-01-01
c c1 1999-01-02
c c2 2003-04-05
c c3 2007-10-02
[/code]
选取结果
[code=BatchFile]a a1 2007-10-30
b b1 2006-04-01
c c1 1999-01-02[/code]

[yxh198358]

select A,max(D) as D ,min(B) as B
from tablename
group by A

[Aylazhang]

就是选出来的D列由 min(B)来决定

[中国风]

select a,min(d),min(b) from t group by a

[internetroot]

select A,D,min(B) as B
from 表名
group by A

[中国风]

select * from ta t where not exists(select 1 from ta where a=t.a and b<t.b)

[fa_ge]

select A,D,min(B) as B
from t
group by A

[Andy-W]

try

SELECT * FROM TableName AS A 
WHERE NOT EXISTS(SELECT 1 FROM TableName AS B WHERE A.A=B.A AND B.B>A.B)

[Andy-W]

错了，应该是把>改成<号。

SELECT * FROM TableName AS A 
WHERE NOT EXISTS(SELECT 1 FROM TableName AS B WHERE A.A=B.A AND B.B<A.B)

[ojuju10]

---1
select * from tab a
where not exists(select 1 from tab where a.a=a and a.b>b )

---2
select a.* from tab a,(select a,min(b) as b from tab group by a) b
where a.a=b.a and a.b=b.b

--3
select a,(select min(b)  from tab where a.a=a) as b from tab a