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  1. Kylin
  2. KYLIN-3883

Kylin supports column count aggregation

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    Details

    • Type: New Feature
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: all
    • Fix Version/s: v3.0.0
    • Component/s: Query Engine
    • Labels:
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      Description

      Kylin目前只支持对常量1进行count聚合预计算，即count(1)，count(col_1)的查询内部全部重写到对count(1)的查询，这样会导致一个问题：当col_1列中存在null值时，count(col_1)的查询结果并不准确。这样就导致Kylin的查询结果和Hive、Spark等不一致。该Patch中，提供了对count(col_1)的支持。

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          is duplicated by

          Bug - A problem which impairs or prevents the functions of the product. KYLIN-2948 Count a column returns the same result as count(*) even if this column has NULL

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed
          links to

          Web Link GitHub Pull Request #528

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              • Assignee:
                xbirbird xiaodongzhang
                Reporter:
                xbirbird xiaodongzhang
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