with cte1 as (
select h.hacker_id as hacker_id, 
    h.name as name, 
    s.score as score, 
    s.challenge_id as challenge_id,
    row_number() over (partition by hacker_id, challenge_id order by score) as rn
from hackers h 
join submissions s
on h.hacker_id = s.hacker_id
-- group by h.hacker_id, h.name
)

select hacker_id, name, sum(score) as total_score
from cte1
where rn=1
group by hacker_id, name
having sum(score) > 0 
order by total_score desc, hacker_id ASC