SELECT 
    hac.hacker_id,
    hac.name
FROM hackers hac
INNER JOIN (
    SELECT 
        sub.hacker_id,
        COUNT(cha.challenge_id) AS cantidad_challenge
    FROM submissions sub
    INNER JOIN challenges cha ON sub.challenge_id = cha.challenge_id
    INNER JOIN difficulty dif ON cha.difficulty_level = dif.difficulty_level
    WHERE sub.score = dif.score
    GROUP BY sub.hacker_id
    HAVING COUNT(cha.challenge_id) > 1
) AS msh ON hac.hacker_id = msh.hacker_id
ORDER BY msh.cantidad_challenge DESC, hac.hacker_id ASC;

SELECT
    hack.Hacker_id,
    hack.name
FROM Hackers AS hack

INNER JOIN Submissions AS sub
    ON hack.hacker_id = sub.hacker_id
    
INNER JOIN Challenges AS chall
    ON sub.challenge_id = chall.challenge_id
    
INNER JOIN Difficulty AS diff
    ON chall.difficulty_level = diff.difficulty_level
    
WHERE 
    sub.score = diff.score
GROUP BY 
    hack.hacker_id, hack.name
HAVING 
    COUNT(sub.submission_id) > 1
ORDER BY
    COUNT(sub.submission_id) DESC, hack.Hacker_id ASC

select s.hacker_id,
        h.name
from hackers h,
    Difficulty d,
    Challenges c,
    submissions s
where h.hacker_id = s.hacker_id
and d.difficulty_level = c.difficulty_level
and s.challenge_id = c.challenge_id
and s.score = (select d.score
              from difficulty d
              where d.difficulty_level = c.difficulty_level)
group by s.hacker_id, h.name
having count(s.challenge_id) > 1
order by count(s.challenge_id) desc ,s.hacker_id 
    

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, s.hacker_id ASC;

SELECT s.hacker_id, h.name
FROM Hackers h
JOIN Submissions s ON s.hacker_id = h.hacker_id
JOIN Challenges c ON s.challenge_id = c.challenge_id
JOIN Difficulty d ON c.difficulty_level = d.difficulty_level 
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, s.hacker_id ASC;