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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-2980) Add CUBE/ROLLUP/GROUPING SETS operator in Table API.
Date Mon, 23 Jan 2017 14:13:27 GMT

    [ https://issues.apache.org/jira/browse/FLINK-2980?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15834599#comment-15834599
] 

ASF GitHub Bot commented on FLINK-2980:
---------------------------------------

Github user twalthr commented on a diff in the pull request:

    https://github.com/apache/flink/pull/3026#discussion_r97299113
  
    --- Diff: docs/dev/table_api.md ---
    @@ -790,6 +790,40 @@ val result = in.groupBy('a).select('a, 'b.sum as 'd);
         </tr>
     
         <tr>
    +      <td><strong>GroupingSets</strong></td>
    +      <td>
    +        <p>Similar to a SQL GROUP BY GROUPING SETS clause. A GROUPING SETS expression
allows to selectively specify the
    +        set of groups that you want to create within a GROUP BY clause.</p>
    +{% highlight scala %}
    +val in = ds.toTable(tableEnv, 'a, 'b, 'c);
    +val result = in.groupingSets(('a, 'b), 'b, ()).select('a, 'b, 'c.sum as 'd);
    +{% endhighlight %}
    +      </td>
    +    </tr>
    +
    +    <tr>
    +      <td><strong>Cube</strong></td>
    +      <td>
    +        <p>Similar to a SQL GROUP BY CUBE clause. A CUBE expression will generate
subtotals for all combinations of the dimensions specified.</p>
    +{% highlight scala %}
    +val in = ds.toTable(tableEnv, 'a, 'b, 'c);
    +val result = in.cube('a, 'b).select('a, 'b, 'c.sum as 'd);
    +{% endhighlight %}
    +      </td>
    +    </tr>
    +
    +    <tr>
    +      <td><strong>Cube</strong></td>
    +      <td>
    +        <p>Similar to a SQL GROUP BY ROLLUP clause. A ROLLUP expression produces
group subtotals from right to left and a grand total.</p>
    --- End diff --
    
    Can you also add an example here?


> Add CUBE/ROLLUP/GROUPING SETS operator in Table API.
> ----------------------------------------------------
>
>                 Key: FLINK-2980
>                 URL: https://issues.apache.org/jira/browse/FLINK-2980
>             Project: Flink
>          Issue Type: New Feature
>          Components: Documentation, Table API & SQL
>            Reporter: Chengxiang Li
>            Assignee: Alexander Chermenin
>         Attachments: Cube-Rollup-GroupSet design doc in Flink.pdf
>
>
> Computing aggregates over a cube/rollup/grouping sets of several dimensions is a common
operation in data warehousing. It would be nice to have them in Table API.



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