@@ -1,3 +1,60 @@
+-- Problem:
+
+/*
+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.
+*/
+
+-------------------------------------------------------------------------------
+
+-- Solution:
+
 SELECT class FROM Courses
 GROUP BY class
 HAVING COUNT(student)>=5