text: SELECT h.Hacker_Id,
         h.Name
      FROM Hackers AS h,
           Challenges AS c,
           Difficulty AS d,
           Submissions AS s
      WHERE h.Hacker_Id = s.Hacker_Id
        AND c.Challenge_Id = s.Challenge_Id
        AND c.Difficulty_Level = d.Difficulty_Level
        AND s.Score = d.Score
      GROUP BY h.Hacker_Id, h.Name
      HAVING COUNT(h.Hacker_Id) > 1
      ORDER BY COUNT(c.Challenge_Id) DESC,
               h.Hacker_Id