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https://issues.apache.org/jira/browse/CALCITE-2247?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16479871#comment-16479871
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Julian Hyde commented on CALCITE-2247:
--------------------------------------
I've reviewed again, and I still have one problem. It is not valid to simplify
{{x <> 1 OR x = 1}} to TRUE, even with unknownAsFalse.
If x is NULL, that expression evaluates to UNKNOWN. If unknownAsFalse, then
that UNKNOWN becomes FALSE.
I rebased your change on top of my dev branch for CALCITE-2314 (see
https://github.com/julianhyde/calcite/tree/2314-verify-rex), and that issue
shows up as the sole failing test.
> 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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