v.23.11Improvement

Rewrite JOIN ON equality with is null check in Analyzer only

Official CH changelog text
Rewrite equality with is null check in JOIN ON section. Experimental Analyzer only. #56538 (vdimir).
Introduces an experimental analyzer-only optimization that rewrites equality conditions combined with IS NULL checks in the JOIN ON clause.

Why it matters

This feature aims to improve query analysis and optimization by handling equality predicates with IS NULL checks more effectively in JOIN operations, potentially enabling better query performance and correctness in edge cases involving NULL values.

How to use it

Currently, this functionality is experimental and available only in the query analyzer phase. Users do not need to change their queries; the analyzer will automatically apply this rewrite when applicable.

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