Unnecessary INNER JOIN
Applies to ✅ Open Source Edition ✅ Express Edition ✅ Professional Edition ✅ Enterprise Edition
An INNER JOIN whose ON clause is always TRUE, or which doesn't actually join on both sides of the JOIN operator can be turned into a CROSS JOIN. In most cases, the CROSS JOIN is accidental, but with that syntax, at least the error can be more easily recognised.
Using Settings.transformPatternsUnnecessaryInnerJoin, the following transformations can be achieved:
-- With Settings.transformPatternsUnnecessaryInnerJoin active, this: SELECT * FROM t JOIN u ON TRUE; -- ... is transformed into the equivalent expression: SELECT * FROM t CROSS JOIN u;
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