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https://issues.apache.org/jira/browse/CALCITE-2247?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16467823#comment-16467823
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Julian Hyde commented on CALCITE-2247:
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[~kgyrtkirk], I reviewed, and pushed a branch with some fix up and a new test
case: https://github.com/julianhyde/calcite/tree/2247-simplify. You are
probably thinking in terms of 2-valued logic, i.e. "unknown-as-false", but
RexSimplify is used for 3-valued logic. It is not valid to simplify "b = 1 OR b
<> 1" to true if b may be null (if you have have set
RexSimplify.unnkownAsFalse(false)).
I tried fixing by wrapping with "IS_NOT_FALSE" rather than "NOT", but was
defeated because the necessary simplification of IS_NOT_FALSE was not
happening. With your changes, RexSimplify.simplifyIs does not always call
simplifyIs2.
Can you revisit and make sure that the new test case passes.
> Add rule to push in condition condition into a related disjunctive expression
> -----------------------------------------------------------------------------
>
> Key: CALCITE-2247
> URL: https://issues.apache.org/jira/browse/CALCITE-2247
> Project: Calcite
> Issue Type: Improvement
> Reporter: Zoltan Haindrich
> Assignee: Zoltan Haindrich
> Priority: Major
>
> Simplify expressions like: {code}a = 1 AND (a = 1 OR a = 2){code} to {code}a
> = 1{code}
> Conditions to apply will be:
> * in an AND condition there exists a comparison(c) and an OR (o)
> * o and c only reference 1 variable
> See HIVE-19097 for more info.
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