[hackerrank] Symmetric Pairs 문제 링크: www.hackerrank.com/challenges/symmetric-pairs/problem?h_r=internal-search Symmetric Pairs | HackerRank Write a query to output all symmetric pairs in ascending order by the value of X. www.hackerrank.com 문제. 짝꿍찾기 - X1 = Y2 and X2 = Y1 - X1 Today I Learned/SQL 문제풀이 2020.11.05
