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https://issues.apache.org/jira/browse/CALCITE-5000?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17526305#comment-17526305
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Xurenhe commented on CALCITE-5000:
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[~julianhyde]
English is not my mother tongue, and I am very sorry to confuse you.
This issue want to eliminate deterministic agg-call, if its arg exists in the
group.
For example:
{code:java}
// origin sql
select max(c1) from tbl group by c1, c2;
// optimized sql
select c1 from tbl group by c1, c2;{code}
How about "Reduce some deterministic agg-calls by its group"?
> Expand rule of `AGGREGATE_REDUCE_FUNCTIONS`, when arg of agg-call is in the
> aggregate's group
> ---------------------------------------------------------------------------------------------
>
> Key: CALCITE-5000
> URL: https://issues.apache.org/jira/browse/CALCITE-5000
> Project: Calcite
> Issue Type: Improvement
> Reporter: Xurenhe
> Assignee: Xurenhe
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.31.0
>
> Time Spent: 2.5h
> Remaining Estimate: 0h
>
> Using calcite's SubstitutionVisitor, we need do a lot work about
> canonicalizing relnode.
> Some sql should be simplified.
> {noformat}
> -- origin sql
> select deptno, salary, max(salary), min(commission)
> from emps
> group by deptno, salary
> -- simplified
> select deptno, salary, salary as expr, min(commission)
> from emps
> group by deptno, salary{noformat}
> It should be simplified, but I didn't find any rule to simplify it.
> This issue is related to CALCITE-4857
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