SQL join challenge

select A.id,H2.name from (
select id,count(ch) as ch2 from (
select C.challenge_id as ch ,D.score,S.score,S.hacker_id as id
from challenges C
inner join difficulty D
on C.difficulty_level = D.difficulty_level
inner join submissions S
on S.challenge_id = C.challenge_id
inner join hackers H
on H.hacker_id = S.hacker_id
where D.score = S.score )
group by id
having count(ch) > 1
) A
inner join hackers H2
on A.id = H2.hacker_id
order by A.ch2 desc,A.id;