README.md

Description

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:

student	class
A	Math
B	English
C	Math
D	Biology
E	Math
F	Computer
G	Math
H	Math
I	Math

Should output:

class
Math

Note: The students should not be counted duplicate in each course.

Solution

select `class` from `courses` group by `class` 
having count(distinct `student`) >= 5;

Note

If you have a better solution, you can star and fork Leetcode-database-problem then create a pull request.