mysql多字段排序，分数班级排序

mysql> select * from student order by class desc,score desc;
+----+-------+-------+-------+
| id | name  | class | score |
+----+-------+-------+-------+
|  6 | user  |     2 |   108 |
|  7 | user1 |     2 |    90 |
|  8 | user  |     2 |    24 |
|  1 | user1 |     1 |   100 |
|  5 | user1 |     1 |   100 |
|  3 | user1 |     1 |    80 |
|  4 | user  |     1 |    62 |
|  2 | user  |     1 |    45 |
+----+-------+-------+-------+
8 rows in set (0.00 sec)

sql语句默认排序是升序，要以哪个字段排序，就order by 字段 desc 。就是这么简单。以班级和分数排序，都降序！