text: /* GET MAX SCORE PER CHALLENGE */
  SELECT Hackers.hacker_id, Hackers.name, SUM(maximum.score) AS total 
  FROM Hackers 
  INNER JOIN (
              SELECT hacker_id, MAX(score) AS score 
              FROM SUBMISSIONS 
              GROUP BY hacker_id, challenge_id) AS maximum 
              ON Hackers.hacker_id = maximum.hacker_id
              GROUP BY Hackers.hacker_id, Hackers.name 
              HAVING total > 0 ORDER BY total DESC, Hackers.hacker_id ASC
  