[jira] [Resolved] (DRILL-3783) Incorrect results : COUNT() over results returned by UNION ALL

["Sean Hsuan-Yi Chu (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/DRILL-3783?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Sean Hsuan-Yi Chu resolved DRILL-3783.
--------------------------------------
    Resolution: Invalid

This is fine. Set-Operator (e.g., Union, Intersect) has the least precedence, so they will be applied later.

> Incorrect results : COUNT(<column-name>) over results returned by UNION ALL 
> ----------------------------------------------------------------------------
>
>                 Key: DRILL-3783
>                 URL: https://issues.apache.org/jira/browse/DRILL-3783
>             Project: Apache Drill
>          Issue Type: Bug
>          Components: Execution - Relational Operators
>    Affects Versions: 1.2.0
>         Environment: 4 node cluster on CentOS
>            Reporter: Khurram Faraaz
>            Assignee: Sean Hsuan-Yi Chu
>            Priority: Critical
>             Fix For: 1.2.0
>
>
> Count over results returned union all query, returns incorrect results. The below query returned an Exception (please se DRILL-2637) that JIRA was marked as fixed, however the query returns incorrect results. 
> {code}
> 0: jdbc:drill:schema=dfs.tmp> select count(c1) from (select cast(columns[0] as int) c1 from `testWindow.csv`) union all (select cast(columns[0] as int) c2 from `testWindow.csv`);
> +---------+
> | EXPR$0  |
> +---------+
> | 11      |
> | 100     |
> | 10      |
> | 2       |
> | 50      |
> | 55      |
> | 67      |
> | 113     |
> | 119     |
> | 89      |
> | 57      |
> | 61      |
> +---------+
> 12 rows selected (0.753 seconds)
> {code}
> Results returned by the query on LHS and RHS of Union all operator are
> {code}
> 0: jdbc:drill:schema=dfs.tmp> select cast(columns[0] as int) c1 from `testWindow.csv`;
> +------+
> |  c1  |
> +------+
> | 100  |
> | 10   |
> | 2    |
> | 50   |
> | 55   |
> | 67   |
> | 113  |
> | 119  |
> | 89   |
> | 57   |
> | 61   |
> +------+
> 11 rows selected (0.197 seconds)
> 0: jdbc:drill:schema=dfs.tmp> select cast(columns[0] as int) c2 from `testWindow.csv`;
> +------+
> |  c2  |
> +------+
> | 100  |
> | 10   |
> | 2    |
> | 50   |
> | 55   |
> | 67   |
> | 113  |
> | 119  |
> | 89   |
> | 57   |
> | 61   |
> +------+
> 11 rows selected (0.173 seconds)
> {code}
> Note that enclosing the queries within correct parentheses returns correct results. We do not want to return incorrect results to user when the parentheses are missing.
> {code}
> 0: jdbc:drill:schema=dfs.tmp> select count(c1) from ((select cast(columns[0] as int) c1 from `testWindow.csv`) union all (select cast(columns[0] as int) c2 from `testWindow.csv`));
> +---------+
> | EXPR$0  |
> +---------+
> | 22      |
> +---------+
> 1 row selected (0.234 seconds)
> {code}



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