[CALCITE-4562] Improve simplification of "expression IS TRUE"

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.27.0
• Labels: pull-request-available
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 31/Mar/21 19:58
• Updated: 03/Jun/21 22:32
• Resolved: 03/Apr/21 01:46

Description

When simplifying "expression IS TRUE", RexSimplify should simplify "expression" in an "unknown as FALSE" context, and this should allow more simplifications than at present.

Currently "(x LIKE '%') IS TRUE" simplifies to "(x IS NOT NULL) IS TRUE", but after this change will simplify to "x IS NOT NULL". The following test illustrates:

    final RexNode ref = input(tVarchar(true, 10), 0);
    checkSimplify(isTrue(like(ref, literal("%"))), "IS NOT NULL($0)");

Similarly "IS FALSE", "IS NOT TRUE", etc.

Issue Links

• links to: GitHub Pull Request #2386