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2025 = (20 + 25)² = 1 + 3 + 5 + … + 89 = 1³ + 2³ + 3³ + … + 9³

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Check out these 2 queries:

Query 1:

SELECT ...
FROM t1
JOIN t2 ON t1.id IN (t2.id1, t2.id2);

Query 2:

SELECT ...
FROM t1
JOIN t2 ON t1.id = t2.id1
UNION
SELECT ...
FROM t1
JOIN t2 ON t1.id = t2.id2;

They both return the same data but since most database engines struggle with OR joins, the latter will outperform the former by at least an order of magnitude.

#SQLTips #DatabaseOptimization #PerformanceTuning