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https://issues.apache.org/jira/browse/CALCITE-3890?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17072624#comment-17072624
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Zoltan Haindrich commented on CALCITE-3890:
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[~Chunwei Lei]: in Hive we have a rule which somewhat does this
I was sure that a Calcite rule adds all the {{is not null}} conditions (and it
is)...but apparently it was not contributed back; and it's still only available
inside Hive.
it might worth taking a look at it:
https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/HiveJoinAddNotNullRule.java
> Infer IS NOT NULL predicate from join
> -------------------------------------
>
> Key: CALCITE-3890
> URL: https://issues.apache.org/jira/browse/CALCITE-3890
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Chunwei Lei
> Assignee: Chunwei Lei
> Priority: Major
>
> We can infer IS NOT NULL predicate from join which implies some columns may
> not be null. For instance,
>
> {code:java}
> select * from a join b on a.id = b.id;
> {code}
> we can infer a.id is not null and b.id is not null.
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