mysql order排序的简单问题。

Question

select *
from  news order by isTop,orderNum desc; +----+--------------+--------+------------+---------------------+----------+---------------------+--------+-------+----------+
| id | newsTitle    | typeId | newsCnt    | newsPic             | newsFrom | newsReleaseTime     | re | isTop | orderNum |
+----+--------------+--------+------------+---------------------+----------+---------------------+--------+-------+----------+
| 28 | 吊死扶伤     | 13     | 范德萨  |                     | 新闻来源 | 2008-11-07 09:37:14 |        |     0 |        2 |
| 24 | 地方法       | 14     | 饭店范德萨|                     | 新闻来源 | 2008-11-07 09:36:48 |        |     0 |        1 |
| 25 | 份额为恶完全 | 13     | 反而大放大|                     | 新闻来源| 2008-11-07 09:36:54 |        |     0 |        1 |
| 26 | 去           | 14     | 额外     |                     | 新闻来源 | 2008-11-07 09:37:01 |        |     0 |        1 |
| 27 | 范德萨范德萨 | 15     | 啊啊     |                     | 新闻来源 | 2008-11-07 09:37:08 |        |     0 |        1 |
| 29 | 发大水       | 14     | 发大水  |                     | 新闻来源 | 2008-11-07 09:37:21 |        |     0 |        1 |
| 30 | 放大         | 14     | 附答案  | 200811071052400.jpg | 新闻来源 | 2008-11-07 10:52:40 |        |     0 |        1 |
| 31 | dfs          | 14     | fa         |                     | 新闻来源 | 2008-11-07 10:55:02 |        |     0 |        1 |
| 32 | a            | 14     | a          |                     | 新闻来源 | 2008-11-07 10:55:08 |        |     0 |        1 |
| 23 | 新闻标题1    | 14     | 新闻内容|                     | 新闻来源 | 2008-11-07 10:58:08 |        |     1 |        1 |
我想先按 istop降序排列，再按ordrNum降序排列 这个顺序，为什么我这个语句不对？达人们帮一下，小弟刚学MYSQL

Answer 1

select *
from  news order by isTop desc,orderNum desc; 

Answer 2

select * from  news order by isTop desc ,orderNum desc;