WITH temp_table AS(
    SELECT a.hacker_id, d.name, a.challenge_id, a.score from submissions as a
    INNER JOIN challenges AS b
    ON a.challenge_id = b.challenge_id
    INNER JOIN difficulty AS c
    on b.difficulty_level = c.difficulty_level
    INNER JOIN hackers as d
    on a.hacker_id = d.hacker_id
    WHERE a.score = c.score
)

-- Now showing details for all hacker who scored full  

SELECT hacker_id, name FROM temp_table
GROUP BY name, hacker_id
HAVING COUNT(score)>1
ORDER BY COUNT(score) desc, hacker_id asc;