select * from tb t where billdate=(select max(billdate) from tb where  goodsid=t.goodsid)

------解决方案--------------------
SQL code
if object_id('[TB]') is not null drop table [TB]
go
create table [TB] (billdate datetime,goodsid int,userdef1 nvarchar(2),userdef2 nvarchar(2),userdef3 nvarchar(2),userdef4 nvarchar(2))
insert into [TB]
select '2011-11-01',1001,'a','b','c','d' union all
select '2011-11-01',1001,'b','c','d','e' union all
select '2011-11-01',3002,'c','d','e','f' union all
select '2011-11-08',3002,'e','f','g','h' union all
select '2011-11-11',3013,'e','f','g','h'

select * from [TB]


SELECT * 
FROM TB 
WHERE EXISTS(SELECT 1 
            FROM TB A 
            WHERE TB.goodsid = goodsid AND TB.USERDEF1 >USERDEF1 )
            
            
/*
billdate    goodsid    userdef1    userdef2    userdef3    userdef4
2011-11-01 00:00:00.000    1001    b    c    d    e
2011-11-08 00:00:00.000    3002    e    f    g    h*/

------解决方案--------------------
SQL code
--小F这个好，有单一值的时候就好用
select * from tb t where userdef1=(select max(userdef1) from tb where  goodsid=t.goodsid)
ORDER BY t.billdate ASC


/*
billdate    goodsid    userdef1    userdef2    userdef3    userdef4
2011-11-01 00:00:00.000    1001    b    c    d    e
2011-11-08 00:00:00.000    3002    e    f    g    h
2011-11-11 00:00:00.000    3013    e    f    g    h*/