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  1. Calcite
  2. CALCITE-896

Remove Aggregate if grouping columns are unique and all functions are splittable

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 1.20.0
    • Component/s: None

      Description

      Remove Aggregate if grouping columns are unique and all functions are splittable. Currently AggregateRemoveRule is only applied if there are no aggregate functions. But we could optimize

      select deptno, count(name) from dept group by deptno

      to

      select deptno, 1 from dept

      because we know deptno is unique, name is not null, and a singleton count applied to a not null column evaluates to 1.

      See AggregateJoinTransposeRule; it already makes use of SqlSplittableAggFunction.

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          Haisheng Yuan

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            • Assignee:
              hyuan Haisheng Yuan
              Reporter:
              julianhyde Julian Hyde

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