[SQL 문제 풀이] Classes With at Least 5 Students (최소 5명 이상의 학생이 있는 수업)

Can you solve this real interview question? Classes With at Least 5 Students - Table: Courses +-------------+---------+ | Column Name | Type | +-------------+---------+ | student | varchar | | class | varchar | +-------------+---------+ (student, class) is the primary key (combination of columns with unique values) for this table. Each row of this table indicates the name of a student and the class in which they are enrolled.   Write a solution to find all the classes that have at least five students. Return the result table in any order. The result format is in the following example.   Example 1: Input: Courses table: +---------+----------+ | 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, so we include it. - English has 1 student, so we do not include it. - Biology has 1 student, so we do not include it. - Computer has 1 student, so we do not include it.