SELECT h.hacker_id, h.name FROM hackers h inner JOIN submissions s ON h.hacker_id = s.hacker_id inner JOIN challenges c ON s.challenge_id = c.challenge_id inner JOIN difficulty d ON c.difficulty_level = d.difficulty_level WHERE s.score = d.score GROUP BY h.hacker_id, h.name HAVING COUNT(s.hacker_id) > 1 ORDER BY COUNT(s.hacker_id) DESC, h.hacker_id ASC;

SELECT

S.hacker_id, 

H.name

FROM

Submissions S

JOIN

Challenges C ON S.challenge_id = C.challenge_id

JOIN

Difficulty D ON C.difficulty_level = D.difficulty_level

JOIN

Hackers H ON S.hacker_id = H.hacker_id

WHERE

S.score = D.score

GROUP BY

S.hacker_id, H.name

HAVING

COUNT(S.challenge_id) > 1

ORDER BY

COUNT(S.challenge_id) DESC, 

20 S.hacker_id ASC;

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

with chall_sub as(SELECT su.hacker_id,su.challenge_id,difficulty_level,max(score) as highscore FROM Submissions su INNER JOIN Challenges ch ON su.challenge_id=ch.challenge_id GROUP BY su.hacker_id,su.challenge_id,difficulty_level)

SELECT Ha.hacker_id,Ha.name FROM Hackers Ha INNER JOIN chall_sub cs ON Ha.hacker_id= cs.hacker_id INNER JOIN Difficulty dif ON cs.difficulty_level= dif.difficulty_level AND cs.highscore=dif.score GROUP BY Ha.hacker_id,Ha.name HAVING COUNT(cs.challenge_id)>1 ORDER BY COUNT(cs.challenge_id) desc,Ha.hacker_id asc

select h.hacker_id, h.name from Hackers h join challenges c on h.hacker_id = c.hacker_id join difficulty d on c.difficulty_level = d.difficulty_level join submissions s on d.score = s.score where s.score = d.score group by h.hacker_id, h.name having count(distinct s.challenge_id) > 1 order by count(distinct s.challenge_id) desc, h.hacker_id asc

(what's wrong with this?)