[jira] [Commented] (CALCITE-4562) Improve simplification of "expression IS TRUE"

["Aleksey Plekhanov (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-4562?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17313564#comment-17313564 ] 

Aleksey Plekhanov commented on CALCITE-4562:
--------------------------------------------

[~julianhyde], I'd like to help with fixing this issue. How can I assign it to myself?

> Improve simplification of "expression IS TRUE"
> ----------------------------------------------
>
>                 Key: CALCITE-4562
>                 URL: https://issues.apache.org/jira/browse/CALCITE-4562
>             Project: Calcite
>          Issue Type: Bug
>            Reporter: Julian Hyde
>            Priority: Major
>
> 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:
> {code}
>     final RexNode ref = input(tVarchar(true, 10), 0);
>     checkSimplify(isTrue(like(ref, literal("%"))), "IS NOT NULL($0)");
> {code}
> Similarly "IS FALSE", "IS NOT TRUE", etc.



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