Available in versions: Dev (3.18)

This is experimental functionality, and as such subject to change. Use at your own risk!

This documentation is for the unreleased development version of jOOQ. Click on the above version links to get this documentation for a supported version of jOOQ.

Unnecessary EXISTS subquery clauses

Applies to ✅ Open Source Edition   ✅ Express Edition   ✅ Professional Edition   ✅ Enterprise Edition

The EXISTS predicate can safely ignore a few of its subquery clauses without changing semantics, including:

All of the above applies only if there are no aggregate functions in the EXISTS subquery.

Using Settings.transformPatternsUnnecessaryExistsSubqueryClauses, the following transformations can be achieved:

-- With Settings.transformPatternsUnnecessaryExistsSubqueryClauses active, this:
SELECT EXISTS (SELECT DISTINCT a, b FROM t);

-- ... is transformed into the equivalent expression:
SELECT EXISTS (SELECT 1 FROM t);

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