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From "sunjincheng (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (FLINK-6465) support FIRST_VALUE on Table API & SQL
Date Wed, 16 Aug 2017 06:41:02 GMT

     [ https://issues.apache.org/jira/browse/FLINK-6465?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

sunjincheng updated FLINK-6465:
-------------------------------
    Description: 
`FIRST_VALUE` is a over window function. In this JIRA. will add `FIRST_VALUE` function support
on TableAPI & SQL.
*Syntax:*
FIRST_VALUE ( [scalar_expression ] )   
    OVER ( [ partition_by_clause ] order_by_clause [ rows_range_clause ] )  
scalar_expression
Is the value to be returned. scalar_expression can be a column, or other arbitrary expression
that results in a single value. Other analytic functions are not permitted.

*NOTE:*
*  `FIRST_VALUE` if used for OVER WINDOW, e.g.: SELECT A, B, FIRST_VALUE(C) OVER (ORDER BY
E) AS firstValue FROM tab.
* OVER WINDOW's retraction is expensive(currently not supported yet), and this JIRA. does
not implement Retract logic of `FIRST_VALUE`.


  was:
`FIRST_VALUE` is a over window function. In this JIRA. will add `FIRST_VALUE` function support
on TableAPI & SQL.
*Syntax:*
FIRST_VALUE ( [scalar_expression ] )   
    OVER ( [ partition_by_clause ] order_by_clause [ rows_range_clause ] )  
scalar_expression
Is the value to be returned. scalar_expression can be a column, or other arbitrary expression
that results in a single value. Other analytic functions are not permitted.

*NOTE:*
`FIRST_VALUE` if used for OVER WINDOW, e.g.:
SELECT A, B, FIRST_VALUE(C) OVER (ORDER BY E) AS firstValue FROM tab.




> support FIRST_VALUE on Table API & SQL
> --------------------------------------
>
>                 Key: FLINK-6465
>                 URL: https://issues.apache.org/jira/browse/FLINK-6465
>             Project: Flink
>          Issue Type: New Feature
>          Components: Table API & SQL
>            Reporter: Hequn Cheng
>            Assignee: sunjincheng
>
> `FIRST_VALUE` is a over window function. In this JIRA. will add `FIRST_VALUE` function
support on TableAPI & SQL.
> *Syntax:*
> FIRST_VALUE ( [scalar_expression ] )   
>     OVER ( [ partition_by_clause ] order_by_clause [ rows_range_clause ] )  
> scalar_expression
> Is the value to be returned. scalar_expression can be a column, or other arbitrary expression
that results in a single value. Other analytic functions are not permitted.
> *NOTE:*
> *  `FIRST_VALUE` if used for OVER WINDOW, e.g.: SELECT A, B, FIRST_VALUE(C) OVER (ORDER
BY E) AS firstValue FROM tab.
> * OVER WINDOW's retraction is expensive(currently not supported yet), and this JIRA.
does not implement Retract logic of `FIRST_VALUE`.



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