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https://issues.apache.org/jira/browse/KYLIN-3883?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16806098#comment-16806098
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ASF subversion and git services commented on KYLIN-3883:
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Commit a9eaf3658eae48abd7401d4d6adee04aadd3275a in kylin's branch
refs/heads/master from zhangxiaodong
[ https://gitbox.apache.org/repos/asf?p=kylin.git;h=a9eaf36 ]
KYLIN-3883 Kylin supports column count aggregation
> Kylin supports column count aggregation
> ---------------------------------------
>
> Key: KYLIN-3883
> URL: https://issues.apache.org/jira/browse/KYLIN-3883
> Project: Kylin
> Issue Type: New Feature
> Components: Query Engine
> Affects Versions: all
> Reporter: xiaodongzhang
> Assignee: xiaodongzhang
> Priority: Major
> Fix For: v3.0.0
>
>
> 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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