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Formatted question description: https://leetcode.ca/all/596.html
596. Classes More Than 5 Students
Level
Easy
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 from table courses where the value of class occurs more than or equal to 5 times. To remove duplicate students, use count(distinct student).
# Write your MySQL query statement below
select class from courses group by class having count(distinct student) >= 5;