Hello coders, today we are going to solve Symmetric Pairs HackerRank Solution in SQL.
You are given a table, Functions, containing two columns: X and Y.
Two pairs (X1, Y1) and (X2, Y2) are said to be symmetric pairs if X1 = Y2 and X2 = Y1.
Write a query to output all such symmetric pairs in ascending order by the value of X. List the rows such that X1 ≤ Y1.
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Solution – Symmetric Pairs in SQL
SELECT X, Y FROM FUNCTIONS F1 WHERE EXISTS (SELECT * FROM FUNCTIONS F2 WHERE F2.Y = F1.X AND F2.X = F1.Y AND F2.X > F1.X) AND (X != Y) UNION SELECT X, Y FROM FUNCTIONS F1 WHERE X = Y AND ( (SELECT COUNT(*) FROM FUNCTIONS WHERE X = F1.X AND Y = F1.X) > 1) ORDER BY X;
Disclaimer: The above Problem (Symmetric Pairs) is generated by Hacker Rank but the Solution is Provided by CodingBroz. This tutorial is only for Educational and Learning Purpose.