[SQL문제풀기] 친구 수 집계하기

문제

solvesql.com

https://solvesql.com/problems/number-of-friends/

SQLite

내가 작성한 정답

select u.user_id, count(e.f) num_friends
from (select user_a_id user_id, user_b_id f from edges
      union all
      select user_b_id user_id, user_a_id f from edges) e
right join users u on e.user_id = u.user_id
group by u.user_id
order by 2 desc, 1;