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https://issues.apache.org/jira/browse/CALCITE-2841?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated CALCITE-2841:
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Labels: pull-request-available (was: )
> Simplification: push negation into Case expression
> --------------------------------------------------
>
> Key: CALCITE-2841
> URL: https://issues.apache.org/jira/browse/CALCITE-2841
> Project: Calcite
> Issue Type: Improvement
> Reporter: Zoltan Haindrich
> Assignee: Zoltan Haindrich
> Priority: Major
> Labels: pull-request-available
>
> Why would this be usefull?
> * right now a boolean CASE expressions are translated into AND/ORs in most
> cases ; "disjunction of conjuctions"
> * AND/OR simplification could "push" the NOT into them; but only after the
> CASE conversion; so the expression becames a "conjunction of disjunctions"
> and all the other simplification rules are working hard to restore order....
> * if the push of NOT would happen earlier it would be better because it could
> address complex cases better
> {code:java}
> @Test public void testNotIntoCase() {
> checkSimplify(
> not(
> case_(
> isTrue(vBool()), vBool(1),
> vBool(2))),
> "CASE(IS TRUE(?0.bool0), NOT(?0.bool1), NOT(?0.bool2))");
> }
> {code}
> actually NOT right now stops the simplification recursion so it would be best
> to also enable that as well; in case NOT is not is not pushed/handled -
> unknownAs need to be negated.
> {code}
> @Test public void testNotRecursion() {
> checkSimplify(
> not(coalesce(nullBool, trueLiteral)),
> "false");
> }
> {code}
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