[jira] [Commented] (HIVE-13452) StatsOptimizer should return no rows on empty table with group by

["Vineet Garg (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-13452?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15649034#comment-15649034 ] 

Vineet Garg commented on HIVE-13452:
------------------------------------

Another example

{code} select (1=1) from t2 group by (1=1); {code}

This returns 1 row irrespective of statsoptimizer.

> StatsOptimizer should return no rows on empty table with group by
> -----------------------------------------------------------------
>
>                 Key: HIVE-13452
>                 URL: https://issues.apache.org/jira/browse/HIVE-13452
>             Project: Hive
>          Issue Type: Bug
>          Components: Logical Optimizer
>            Reporter: Ashutosh Chauhan
>            Assignee: Pengcheng Xiong
>
> {code}
> create table t1 (a int);
> analyze table t1 compute statistics;
> analyze table t1 compute statistics for columns;
> select count(1) from t1 group by 1;
> set hive.compute.query.using.stats=true;
> select count(1) from t1 group by 1;
> {code}
> In both cases result set should be empty. However, with statsoptimizer on Hive returns one row with value 0.



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