[HackerRank SQL] Contest Leaderboard

문제 link
https://www.hackerrank.com/challenges/contest-leaderboard/problem

Code link
https://github.com/JamesJung01/Hackerrank_sql/blob/main/02_Medium/Contest_Leaderboard.sql

SELECT h.hacker_id,
       h.name,
       SUM(s.score)
FROM hackers AS h JOIN (SELECT hacker_id, challenge_id, max(score) AS score
                        FROM submissions
                        GROUP BY hacker_id, challenge_id) AS s
ON h.hacker_id = s.hacker_id
GROUP BY h.hacker_id, h.name
HAVING SUM(s.score) > 0
ORDER BY SUM(s.score) DESC, h.hacker_id