WITH cte AS (
        SELECT
            h.hacker_id,
            h.name,
            MAX(s.score) as max_scr
        FROM
            hackers h
            INNER JOIN submissions s ON s.hacker_id = h.hacker_id
        WHERE
            s.score != 0
        GROUP BY
            h.hacker_id, h.name, s.challenge_id)

SELECT
    hacker_id,
    name,
    SUM(max_scr)
FROM
    cte
GROUP BY
    hacker_id, name
ORDER BY
    SUM(max_scr) DESC, hacker_id