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.

Merge CASE .. WHEN and ELSE clauses

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

When a searched CASE expression's last WHEN clause returns the same value as the ELSE clause, then the WHEN clause is redundant. If it's the only WHEN clause, then the entire CASE exression is redundant.

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

-- With Settings.transformPatternsCaseMergeWhenElse active, this:
SELECT 
  CASE WHEN a = b THEN x WHEN c = d THEN y ELSE y END,
  CASE WHEN a = b THEN x ELSE x END
FROM tab;

-- ... is transformed into the equivalent expression:
SELECT
  CASE WHEN a = b THEN x ELSE y END,
  x
FROM tab;

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