LeetCode: Classes More Than Students

LeetCode: Classes More Than Students

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:

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

Should output:

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+---------+
| class   |
+---------+
| Math    |
+---------+

Note:

The students should not be counted duplicate in each course.

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# Write your MySQL query statement below
select class from (select distinct student, class from courses) t group by class having count(*) >=5;