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https://issues.apache.org/jira/browse/CALCITE-3192?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17031543#comment-17031543
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Zoltan Haindrich commented on CALCITE-3192:
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I see now; so you are after whether that issue would be fixed by this patch;
what happens without this patch is that:
{code}
(1<a) or (a<3 and (b=2))
-- for which the following rewrite is valid:
(a>1) or (a<3 and a<=1 and b=2)
-- but...because of implementation details...the a<=1 is introduced as a
predicate; which could be described like:
(a>1) or ( a<3 and b=2 | when a<=1)
-- which is rewritten to (because a<=1 was a predicate)
(a>1) or (b=2)
{code}
...in then end it will answer the a=null case incorrectly as you have described
I hope this helps clean up things
> Simplification may weaken OR conditions containing inequalities
> ---------------------------------------------------------------
>
> Key: CALCITE-3192
> URL: https://issues.apache.org/jira/browse/CALCITE-3192
> Project: Calcite
> Issue Type: Bug
> Reporter: Jess Balint
> Assignee: Zoltan Haindrich
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.21.0
>
> Time Spent: 50m
> Remaining Estimate: 0h
>
> RexSimplify is transforming
> * {{OR(AND(>(999, $8), =($2, 'Franklin')), <(100, $8))}}
> * to {{OR(=($2, 'Franklin'), <(100, $8))}}
> the predicates are accumulated in {{simplifyOrTerms()}} but not discarded
> when iterating the second time
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