select??sum(case when a.user_id=1 then b.kills end) as 'wukong',

sum(case when a.user_id=2 then b.kills end) as 'bajie',

sum(case when a.user_id=3 then b.kills end) as 'shaseng'

from user a join user_kills b on a.user_id = b.user_id group by b.user_id;

結果如下：

+--------+-------+---------+

| wukong | bajie | shaseng |

+--------+-------+---------+

|? 50722 |? NULL |? ? NULL |

| ? NULL | 15310 |? ? NULL |

| ? NULL |? NULL |? ? 2100 |

+--------+-------+---------+

3 rows in set (0.00 sec)