Classes with more than 5 students 3-10-22

link ---- https://www.codingninjas.com/codestudio/problems/classes-more-than-5-students_2105464?topList=top-100-sql-problems

Problem Statement

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    |
+---------+


-----------------------------solution ----------------------------



select class from courses 
group by 1
having count (*) >4

------------------solution 2 -----------------------

SELECT
    class
FROM
    (SELECT
        class, COUNT(DISTINCT student) AS num
    FROM
        courses
    GROUP BY class) AS temp_table
WHERE
    num >= 5
;