SQL 문제 풀이 챌린지(24/25) - 세 명이 서로 친구인 관계 찾기

저작권 문제로 인해, 직접 작성한 쿼리문만 공개.

 

 

 

24. 세 명이 서로 친구인 관계 찾기
https://solvesql.com/problems/friend-group-of-3/

SELECT
    e1.user_a_id AS user_a_id,
    e1.user_b_id AS user_b_id,
    e2.user_b_id AS user_c_id
FROM
    edges e1
INNER JOIN edges e2 ON e1.user_b_id = e2.user_a_id
INNER JOIN edges e3 ON e1.user_a_id = e3.user_a_id AND e3.user_b_id = e2.user_b_id
WHERE
    3820 IN (e1.user_a_id, e1.user_b_id, e2.user_b_id)
    AND e1.user_a_id < e1.user_b_id
    AND e1.user_b_id < e2.user_b_id
ORDER BY
    e1.user_a_id, e1.user_b_id, e2.user_b_id