Classes More Than 5 Students
Desicription
There is a table courses with columns: student and class
Please list out all classes which have more than or equal to 5 students.
For example, the table:
代码语言：javascript复制 --------- ------------
| student | class |
--------- ------------
| A | Math |
| B | English |
| C | Math |
| D | Biology |
| E | Math |
| F | Computer |
| G | Math |
| H | Math |
| I | Math |
--------- ------------ Should output:
代码语言：javascript复制 ---------
| class |
---------
| Math |
--------- Note: The students should not be counted duplicate in each course.
Solution
代码语言：javascript复制select class from courses group by class having count(distinct student) >= 5;
