No code changes completed due session quota exhaustion

[Copilot]

Work on this issue did not reach implementation before the session quota was exhausted.

• Issue summary

  • AlaSQL rejects JOIN ... ON <expr> IS NOT NULL forms that other SQL engines accept, including cases like ON +(90) IS NOT NULL and ON NOT NULL IS NOT NULL.

• Session outcome

  • No parser or test changes were completed in this session.
  • A follow-up session should add a focused regression test for the issue and update the parser to accept IS [NOT] NULL in JOIN ... ON expressions.

Example of the currently failing form:

SELECT DISTINCT *
FROM tab2 cor0
JOIN tab2 cor1 ON +(90) IS NOT NULL,
     tab0 AS cor2;

• Fixes JOIN ON xxx IS NOT NULL #468