596.(Easy)超过5名学生的课
+---------+------------+
| student | class |
+---------+------------+
| A | Math |
| B | English |
| C | Math |
| D | Biology |
| E | Math |
| F | Computer |
| G | Math |
| H | Math |
| I | Math |
+---------+------------++---------+
| class |
+---------+
| Math |
+---------+
提示:
学生在每个课中不应被重复计算。Solution
Last updated