easy_596.sql

/*
## easy: 596. Classes More Than 5 Students

### TASK 

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: # Write your MySQL query statement below
SELECT 
    class
FROM 
    courses
GROUP BY 
    class
HAVING 
    COUNT(DISTINCT student) >=5
;