示例表如下：
A, B
yumi, 15
yumi, 5
yumi, 100
tudou, 10
tudou, 12
tudou, 9
fanqie, 20
fanqie, 26
fanqie, 18
fanqie, 12
fanqie, 8
如上表中，希望筛选A列的商品中，只要B列存在大于15的记录，那么A列所有该商品的记录均被筛选出来。
筛选结果应该是（土豆由于不满足条件，被过滤掉了，而玉米、番茄的记录则全部保留）：
A, B
yumi, 15
yumi, 5
yumi, 100
fanqie, 20
fanqie, 26
fanqie, 18
fanqie, 12
fanqie, 8
谢谢大侠啊！
http://bbs.csdn.net/topics/392084759
mysql> select * from fruits;
+--------+--------+
| name | number |
+--------+--------+
| yumi | 15 |
| yumi | 5 |
| yumi | 100 |
| tudou | 10 |
| tudou | 12 |
| tudou | 9 |
| fanqie | 20 |
| fanqie | 26 |
| fanqie | 18 |
| fanqie | 12 |
| fanqie | 8 |
+--------+--------+
11 rows in set (0.00 sec)
mysql> select A.name,A.number from fruits A,(select distinct(name) from fruits where number>15) B where A.name = B.name;
+--------+--------+
| name | number |
+--------+--------+
| yumi | 15 |
| yumi | 5 |
| yumi | 100 |
| fanqie | 20 |
| fanqie | 26 |
| fanqie | 18 |
| fanqie | 12 |
| fanqie | 8 |
+--------+--------+
8 rows in set (0.01 sec)
假设那张有A,B字段的表叫做 test 表
select * from test m where m.a in(select v.a from tesst v where v.b>=15)
谢谢，发现还是H7_N18 的算法更为节省时间，谢谢！@H7_N18