Leetcode 1194. 锦标赛优胜者

https://leetcode-cn.com/problems/tournament-winners/

select a.group_id,a.player_id from(
select *,row_number() over(partition by a.group_id order by a.score desc)id from(
select  a.group_id,a.player_id,sum(a.score) score from(
select a.group_id,a.player_id,sum(ifnull(b.first_score,0)) score
from Players a left join Matches b on a.player_id=b.first_player 
group by a.group_id,a.player_id
union all 
select a.group_id,a.player_id,sum(ifnull(b.second_score,0)) score
from Players a left join Matches b on a.player_id=b.second_player
group by a.group_id,a.player_id
)a 
group by a.group_id,a.player_id
)a 
)a where a.id=1