SELECT hackers.hacker_id, hackers.name FROM hackers
JOIN submissions ON submissions.hacker_id = hackers.hacker_id
JOIN challenges ON challenges.challenge_id = submissions.challenge_id
JOIN difficulty ON difficulty.difficulty_level = challenges.difficulty_level
WHERE difficulty.score = submissions.score
GROUP BY 1, 2
HAVING COUNT(*) > 1
ORDER BY COUNT(*) DESC, hackers.hacker_id;