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https://issues.apache.org/jira/browse/FLINK-7144?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Flink Jira Bot updated FLINK-7144:
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Labels: auto-unassigned stale-major (was: auto-unassigned)
I am the [Flink Jira Bot|https://github.com/apache/flink-jira-bot/] and I help
the community manage its development. I see this issues has been marked as
Major but is unassigned and neither itself nor its Sub-Tasks have been updated
for 30 days. I have gone ahead and added a "stale-major" to the issue". If this
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> Optimize multiple LogicalAggregate into one
> -------------------------------------------
>
> Key: FLINK-7144
> URL: https://issues.apache.org/jira/browse/FLINK-7144
> Project: Flink
> Issue Type: Improvement
> Components: Table SQL / Legacy Planner
> Reporter: Jark Wu
> Priority: Major
> Labels: auto-unassigned, stale-major
>
> When applying multiple GROUP BY, and no aggregates or expression in the first
> GROUP BY, and the second GROUP fields is a subset of first GROUP fields.
> Then the first GROUP BY can be removed.
> Such as the following SQL ,
> {code}
> SELECT a FROM (SELECT a,b,c FROM MyTable GROUP BY a, b, c) GROUP BY a
> {code}
> should be optimized into
> {code}
> DataStreamGroupAggregate(groupBy=[a], select=[a])
> DataStreamCalc(select=[a])
> DataStreamScan(table=[[_DataStreamTable_0]])
> {code}
> but get:
> {code}
> DataStreamGroupAggregate(groupBy=[a], select=[a])
> DataStreamCalc(select=[a])
> DataStreamGroupAggregate(groupBy=[a, b, c], select=[a, b, c])
> DataStreamScan(table=[[_DataStreamTable_0]])
> {code}
> I looked for the Calcite built-in rules, but can't find a match one. So maybe
> we should implement one , and maybe we should implement it in Calcite.
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