急求SQL语句

CREATE TABLE `tab` (
  `name` varchar(10) NOT NULL,
  `money` varchar(10) NOT NULL,
  `mydate` datetime NOT NULL,
  KEY `name` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

#
# 导出表中的数据 `tab`
#

INSERT INTO `tab` (`name`, `money`, `mydate`) VALUES ('wsz', '10', '2011-08-01 09:30:55'),
('wsz', '10', '2011-08-01 09:30:57'),
('wsz', '10', '2011-08-01 09:40:57'),
('wsz', '10', '2011-08-01 09:40:27'),
('yrm', '22', '2011-08-01 09:38:55'),
('yrm', '10', '2011-08-01 09:43:18'),
('yrm', '10', '2011-08-01 09:43:19'),
('yrm', '15', '2011-08-01 09:51:15'),
('yrm', '15', '2011-08-01 09:51:15'),
('yrm', '10', '2011-08-01 09:57:15');


--------------------------------
要取出：
只要时间是今天的，并且时间要小于2011-08-01 09:57分以前的记录。重复的用户要合并，钱也要合并，结果如下：

wsz 20
yrm 25

补充一下，时间是记到以‘分’为准，分以前相同的，秒不同也可以合并

SQL code

mysql> select * from tab;
+------+-------+---------------------+
| name | money | mydate              |
+------+-------+---------------------+
| wsz  | 10    | 2011-08-01 09:30:55 |
| wsz  | 10    | 2011-08-01 09:30:57 |
| wsz  | 10    | 2011-08-01 09:40:57 |
| wsz  | 10    | 2011-08-01 09:40:27 |
| yrm  | 22    | 2011-08-01 09:38:55 |
| yrm  | 10    | 2011-08-01 09:43:18 |
| yrm  | 10    | 2011-08-01 09:43:19 |
| yrm  | 15    | 2011-08-01 09:51:15 |
| yrm  | 15    | 2011-08-01 09:51:15 |
| yrm  | 10    | 2011-08-01 09:57:15 |
+------+-------+---------------------+
10 rows in set (0.00 sec)

mysql> select name,sum(money)
    -> from tab
    -> where mydate<='2011-08-01 09:57'
    -> group by name;
+------+------------+
| name | sum(money) |
+------+------------+
| wsz  |         40 |
| yrm  |         72 |
+------+------------+
2 rows in set (0.02 sec)

mysql>

实在无法理解你的wsz 20是怎么算出来的？！以下这四条记录不符合你的要求吗？ （时间是今天的，并且时间要小于2011-08-01 09:57分以前的记录）
| wsz | 10 | 2011-08-01 09:30:55 |
| wsz | 10 | 2011-08-01 09:30:57 |
| wsz | 10 | 2011-08-01 09:40:57 |
| wsz | 10 | 2011-08-01 09:40:27 |

首先，谢谢狼哥！
| wsz | 10 | 2011-08-01 09:30:55 |
| wsz | 10 | 2011-08-01 09:30:57 |
以上09:30这二条算一条
| wsz | 10 | 2011-08-01 09:40:57 |
| wsz | 10 | 2011-08-01 09:40:27 |
这二条09:40算一条

09:30的10元+09:40的10元

SQL code

mysql> select name,sum(money)
    -> from tab a
    -> where mydate<'2011-08-01 09:57'
    -> and not exists (
    ->  select 1 from tab where name=a.name
    ->  and mydate-interval second(mydate) second=a.mydate-interval second(a.myd
ate) second
    ->  and mydate>a.mydate)
    -> group by name;
+------+------------+
| name | sum(money) |
+------+------------+
| wsz  |         20 |
| yrm  |         62 |
+------+------------+
2 rows in set (0.00 sec)

mysql>

仍然无法无天理解你的yrm 25是怎么来的。

| yrm | 22 | 2011-08-01 09:38:55 |这条钱不重复不要
| yrm | 10 | 2011-08-01 09:43:18 |
| yrm | 10 | 2011-08-01 09:43:19 |
以上这二条算一条
| yrm | 15 | 2011-08-01 09:51:15 |
| yrm | 15 | 2011-08-01 09:51:15 |
以上这二条算一条
| yrm | 10 | 2011-08-01 09:57:15 |这条时间不符合不要
-----------------

10+15=25