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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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