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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-6228) Integrating the OVER windows in the Table API
Date Thu, 20 Apr 2017 22:11:06 GMT

    [ https://issues.apache.org/jira/browse/FLINK-6228?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15977659#comment-15977659
] 

ASF GitHub Bot commented on FLINK-6228:
---------------------------------------

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

    https://github.com/apache/flink/pull/3743#discussion_r112455555
  
    --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/table/api/table.scala
---
    @@ -810,6 +810,47 @@ class Table(
         new WindowedTable(this, window)
       }
     
    +  /**
    --- End diff --
    
    Extend docs to
    
    ```
      /**
        * Defines over-windows on the records of a table.
        *
        * An over-window defines for each record an interval of records over which aggregation

        * functions can be computed.
        *
        * Example:
        *
        * {{{
        *   table
        *     .window(Over partitionBy 'c orderBy 'rowTime preceding 10.seconds as 'ow)
        *     .select('c, 'b.count over 'ow, 'e.sum over 'ow)
        * }}}
        *
        * __Note__: Computing over window aggregates on a streaming table is only a parallel
operation
        * if the window is partititioned. Otherwise, the whole stream will be processed by
a single
        * task, i.e., with parallelism 1.
        *
        * __Note__: Over-windows for batch tables are currently not supported.
        *
        * @param overWindows windows that specify the record interval over which aggregations
are
        *                    computed.
        * @return An OverWindowedTable to specify the aggregations.
        */
    ```


> Integrating the OVER windows in the Table API
> ---------------------------------------------
>
>                 Key: FLINK-6228
>                 URL: https://issues.apache.org/jira/browse/FLINK-6228
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Table API & SQL
>            Reporter: sunjincheng
>            Assignee: sunjincheng
>
> Syntax:
> {code}
> table
>    .overWindows(
>     (Rows|Range [ partitionBy value_expression , ... [ n ]] [ orderBy order_by_expression]

>       (preceding  UNBOUNDED|value_specification.(rows|milli|second|minute|hour|day|month|year)|CURRENTROW)
>      [following UNBOUNDED|value_specification.(rows|milli|second|minute|hour|day|month|year)|CURRENTROW]
>     as alias,...[n])
>    )
>   .select( [col1,...[n]], (agg(col1) OVER overWindowAlias, … [n])
> {code}
> Implement restrictions:
> * All OVER clauses in the same SELECT clause must be exactly the same.
> * The PARTITION BY clause is optional (no partitioning results in single threaded execution).
> * The ORDER BY Before the [FLINK-5884|https://issues.apache.org/jira/browse/FLINK-5884]
 implementation orderBy may only have ‘rowtime/’proctime(for stream)/‘specific-time-field(for
batch).
> * FOLLOWING is not supported.
> User interface design document [See | https://docs.google.com/document/d/13Z-Ovx3jwtmzkSweJyGkMy751BouhuJ29Y1CTNZt2DI/edit#]



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