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https://issues.apache.org/jira/browse/HIVE-15758?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16035672#comment-16035672
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Ashutosh Chauhan commented on HIVE-15758:
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Classic paper in this area is :
https://pdfs.semanticscholar.org/0bfa/e505ad588d00d4b204acf8ba4b5646eac244.pdf
You may verify if your rewrite is consistent with it.
> Allow correlated scalar subqueries with aggregates which has non-equi join
> predicates
> -------------------------------------------------------------------------------------
>
> Key: HIVE-15758
> URL: https://issues.apache.org/jira/browse/HIVE-15758
> Project: Hive
> Issue Type: Sub-task
> Components: Logical Optimizer
> Reporter: Vineet Garg
> Assignee: Vineet Garg
> Labels: sub-query
>
> Queries such as
> {code} select * from part where p_size <> (select count(p_size) from part pp
> where part.p_type <> pp.p_type); {code} are currently not allowed since HIVE
> doesn't know how to rewrite such queries to preserve the correctness for
> cases when there is zero row
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