Classes With at Least 5 Students

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Medium

Description

You are given a Courses table that records which students are enrolled in which classes. Write a SQL query to find all classes that have at least 5 students enrolled. Return the result in any order.

Database Schema

Courses

Column Name	Example Value
student	A
class	Math

Example

Courses

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

Output

class
Math

Explanation:

Math has 6 students - qualifies. English has 1, Biology has 1, Computer has 1 - none qualify. Only Math is returned.

Approach hint

Start with a simple approach, explain the trade-off, then move toward a cleaner or more scalable solution.

Common mistake

Skipping assumptions, edge cases, or trade-offs can make an otherwise good answer feel incomplete.