text: /**
   * problem url: https://leetcode.com/problems/classes-more-than-5-students/
   * leetcode profile url:  https://leetcode.com/jamsrandorj/
   * solved by jama
  **/
  
  
  /* Write your PL/SQL query statement below */
  SELECT c.class as "class" 
  FROM courses c 
  GROUP BY c.class
  HAVING COUNT(DISTINCT c.student) >= 5;
              