帮忙写SQL语句，在线等

[xyqiqi]

有两张表
a: billno checkdate
001 2004-10-12 12:00:00
002 2004-10-12 13:00:00
b: billno goodscode
001 01
001 02
001 03
002 02
002 03
002 04
b为a的明细表，现在要查询每个goodscode中checkdate最小的sql语句.

[xyqiqi]

如果把billno列加上不就不对了吗？

[watercoolcool]

t1: a b
-------------------
1 a
2 b
3 c

t2: a b c
----------------------
1 a 1
1 b 1
2 c 1

求一语句从t1中筛掉t2中存在的数据后检索出表
t3: a b
--------------
2 b
3 c

[软件钢琴师]

--测试：
create table aa (billno varchar(10),checkdate varchar(20))
insert into aa select '001','2004-10-12 12:00:00'
union all select '002','2004-10-12 13:00:00'

create table bb (billno varchar(10),goodscode varchar(20))
insert into bb select '001','01'
union all select
'001','02'union all select
'001','03'union all select
'002','02'union all select
'002','03'union all select
'002','04'

--查询：
select aa.*,bb.goodscode from aa
left join (select billno,goodscode=min(goodscode) from bb group by billno )bb
on aa.billno=bb.billno

[xyqiqi]

是checkdate最小

[软件钢琴师]

上面的那个查询有问题，改成这样
----查询：
select goodscode ,min(checkdate) from (select bb.goodscode, aa.checkdate from aa ,bb where aa.billno=bb.billno) aa
group by aa.goodscode
结果：
goodcode 无列名
01 2004-10-12 12:00:00
02 2004-10-12 12:00:00
03 2004-10-12 12:00:00
04 2004-10-12 13:00:00

[Andy__Huang]

select a.*,b.goodscode from a
left join (select billno,goodscode=min(goodscode) from b group by billno )b
on a.billno=b.billno

[mgsray]

select goodscode ,min(checkdate) from (select b.goodscode, a.checkdate from a ,b where a.billno=b.billno) a
group by a.goodscode

[xyqiqi]

这样不是和刚才的那个差不多。
我现在是主表和明细表中的数据都要