--测试环境
create table #aa
(
    date    datetime
,    [name]    varchar(20)
,    score   int
)
insert into #aa
select '2012-07-01','张三',80 union all
select '2012-07-01','李四',85 union all
select '2012-07-01','王二',70 union all
select '2012-07-01','麻子',80 union all

select '2012-07-02','李四',90 union all
select '2012-07-02','张三',85 union all
select '2012-07-02','麻子',70 union all
select '2012-07-02','王二',80 union all

select '2012-07-03','李四',60 union all
select '2012-07-03','张三',85 union all
select '2012-07-03','王二',85 union all
select '2012-07-03','麻子',70 

/*
结果：
    date            name    score     place
    2012-07-01        李四    85          1    
    2012-07-01        麻子    80          2
    2012-07-01        张三    80          2
    2012-07-01        王二    70          4
                                        
    2012-07-02        李四    90        1    
    2012-07-02        张三    85        2
    2012-07-02        王二    80        3
    2012-07-02        麻子    70        4

    2012-07-03        王二    85        1
    2012-07-03        张三    85        1
    2012-07-03        麻子    70        3
    2012-07-03        李四    60        4
*/

select * ,rank()over(partition by date order by date,score desc) from #aa

date                    name                 score       
----------------------- -------------------- ----------- --------------------
2012-07-01 00:00:00.000 李四                   85          1
2012-07-01 00:00:00.000 麻子                   80          2
2012-07-01 00:00:00.000 张三                   80          2
2012-07-01 00:00:00.000 王二                   70          4
2012-07-02 00:00:00.000 李四                   90          1
2012-07-02 00:00:00.000 张三                   85          2
2012-07-02 00:00:00.000 王二                   80          3
2012-07-02 00:00:00.000 麻子                   70          4
2012-07-03 00:00:00.000 张三                   85          1
2012-07-03 00:00:00.000 王二                   85          1
2012-07-03 00:00:00.000 麻子                   70          3
2012-07-03 00:00:00.000 李四                   60          4

(12 行受影响)

------解决方案--------------------
SQL code
select *,rank()over(partition by date order by score desc) as place, from #aa 
--sorry

------解决方案--------------------
楼主都知道开窗函数了，partition 分组一下就ok了...