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From "sunjincheng (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (FLINK-5990) Add event time OVER ROWS BETWEEN x PRECEDING aggregation to SQL
Date Wed, 08 Mar 2017 06:24:37 GMT

     [ https://issues.apache.org/jira/browse/FLINK-5990?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

sunjincheng updated FLINK-5990:
-------------------------------
    Description: 
The goal of this issue is to add support for OVER ROWS aggregations on event time streams
to the SQL interface.

Queries similar to the following should be supported:
{code}
SELECT 
  a, 
  SUM(b) OVER (PARTITION BY c ORDER BY rowTime() ROWS BETWEEN 2 PRECEDING AND CURRENT ROW)
AS sumB,
  MIN(b) OVER (PARTITION BY c ORDER BY rowTime() ROWS BETWEEN 2 PRECEDING AND CURRENT ROW)
AS minB
FROM myStream
{code}

The following restrictions should initially apply:
- 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 clause may only have rowTime() as parameter. rowTime() is a parameterless scalar
function that just indicates event time mode.
- UNBOUNDED PRECEDING is not supported 
- FOLLOWING is not supported.

The restrictions will be resolved in follow up issues. If we find that some of the restrictions
are trivial to address, we can add the functionality in this issue as well.

This issue includes:
- Design of the DataStream operator to compute OVER ROW aggregates
- Translation from Calcite's RelNode representation (LogicalProject with RexOver expression).

> Add event time OVER ROWS BETWEEN x PRECEDING aggregation to SQL
> ---------------------------------------------------------------
>
>                 Key: FLINK-5990
>                 URL: https://issues.apache.org/jira/browse/FLINK-5990
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Table API & SQL
>            Reporter: sunjincheng
>            Assignee: sunjincheng
>
> The goal of this issue is to add support for OVER ROWS aggregations on event time streams
to the SQL interface.
> Queries similar to the following should be supported:
> {code}
> SELECT 
>   a, 
>   SUM(b) OVER (PARTITION BY c ORDER BY rowTime() ROWS BETWEEN 2 PRECEDING AND CURRENT
ROW) AS sumB,
>   MIN(b) OVER (PARTITION BY c ORDER BY rowTime() ROWS BETWEEN 2 PRECEDING AND CURRENT
ROW) AS minB
> FROM myStream
> {code}
> The following restrictions should initially apply:
> - 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 clause may only have rowTime() as parameter. rowTime() is a parameterless
scalar function that just indicates event time mode.
> - UNBOUNDED PRECEDING is not supported 
> - FOLLOWING is not supported.
> The restrictions will be resolved in follow up issues. If we find that some of the restrictions
are trivial to address, we can add the functionality in this issue as well.
> This issue includes:
> - Design of the DataStream operator to compute OVER ROW aggregates
> - Translation from Calcite's RelNode representation (LogicalProject with RexOver expression).



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