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https://issues.apache.org/jira/browse/FLINK-5655?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15867369#comment-15867369
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Haohui Mai commented on FLINK-5655:
-----------------------------------
I'm particularly interested in the part that compiles the sliding windows from
Calcite down to the DataStream operators.
Maybe a dumb question -- I wonder, is it possible to specify sliding grouped
windows introduced in FLINK-4691 in this syntax? Essentially I am looking at
something that directly maps to the sliding windows in the {{DataStream}} /
{{Table}} APIs.
Essentially I'm looking for
https://ci.apache.org/projects/flink/flink-docs-release-1.2/dev/windows.html#sliding-windows.
I can see there are two possible ways to express the sliding windows:
{noformat}
1. SELECT SUM(b) OVER(PARTITION BY SlidingWindowGap(...) RANGE BETWEEN INTERVAL
'1' HOUR PRECEDING AND CURRENT ROW)) FROM table
2. SELECT SUM(b) FROM table GROUP BY SlidingWindow(size, interval)
{noformat}
The approach (2) is implemented by
https://msdn.microsoft.com/en-us/library/azure/dn835051.aspx.
My question is that are (1) and (2) semantically equivalent? What is the right
way to express grouped sliding windows?
> Add event time OVER RANGE BETWEEN x PRECEDING aggregation to SQL
> ----------------------------------------------------------------
>
> Key: FLINK-5655
> URL: https://issues.apache.org/jira/browse/FLINK-5655
> Project: Flink
> Issue Type: Sub-task
> Components: Table API & SQL
> Reporter: Fabian Hueske
> Assignee: Shaoxuan Wang
>
> The goal of this issue is to add support for OVER RANGE 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() RANGE BETWEEN INTERVAL '1'
> HOUR PRECEDING AND CURRENT ROW) AS sumB,
> MIN(b) OVER (PARTITION BY c ORDER BY rowTime() RANGE BETWEEN INTERVAL '1'
> HOUR 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 processing time mode.
> - UNBOUNDED PRECEDING is not supported (see FLINK-5658)
> - 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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