Symmetric Pairs 문제 질문드립니다!

정말 감사합니다!!!! 답변 참고해서 아래처럼하니까 되네요!!! SELECT f1.x, f1.y FROM functions AS f1 INNER JOIN functions AS f2 ON f1.x=f2.y AND f1.y=f2.x GROUP BY f1.x, f1.y HAVING count(*)>=2 or f1.x ORDER BY f1.x

TOP Earners 해설 관련 질문드립니다!

감사합니다 :D