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https://issues.apache.org/jira/browse/FLINK-6232?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16087073#comment-16087073
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ASF GitHub Bot commented on FLINK-6232:
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Github user fhueske commented on the issue:
https://github.com/apache/flink/pull/4324
Thanks for the review @wuchong.
The `DataStream` join semantics can be implemented with this join by first
window grouping both inputs with a UDAGG that collects all records in a list,
and then joins the lists on the same time with `left.t BETWEEN right.t AND
right.t` (we do not support a single `==` predicate on time so we need `>=` and
`<=`, but this could be added, IMO). And then a UDF that crosses the lists.
I think this is how you would need to do it in SQL (you could use UNNEST to
do the Cartesian product). The Table API could have a syntactic shortcut for
that but the internal logical representation would again be the same.
Not sure if it adds much value. I think the windowed join semantics of this
PR are nicer because they do not have cut-off points at the window boundaries
(two records could be only 3 msecs apart but would not join because they are in
different tumbling windows).
> Support proctime inner equi-join between two streams in the SQL API
> -------------------------------------------------------------------
>
> Key: FLINK-6232
> URL: https://issues.apache.org/jira/browse/FLINK-6232
> Project: Flink
> Issue Type: Sub-task
> Components: Table API & SQL
> Reporter: hongyuhong
> Assignee: hongyuhong
>
> The goal of this issue is to add support for inner equi-join on proc time
> streams to the SQL interface.
> Queries similar to the following should be supported:
> {code}
> SELECT o.proctime, o.productId, o.orderId, s.proctime AS shipTime
> FROM Orders AS o
> JOIN Shipments AS s
> ON o.orderId = s.orderId
> AND o.proctime BETWEEN s.proctime AND s.proctime + INTERVAL '1' HOUR;
> {code}
> The following restrictions should initially apply:
> * The join hint only support inner join
> * The ON clause should include equi-join condition
> * The time-condition {{o.proctime BETWEEN s.proctime AND s.proctime +
> INTERVAL '1' HOUR}} only can use proctime that is a system attribute, the
> time condition only support bounded time range like {{o.proctime BETWEEN
> s.proctime - INTERVAL '1' HOUR AND s.proctime + INTERVAL '1' HOUR}}, not
> support unbounded like {{o.proctime > s.protime}}, and should include both
> two stream's proctime attribute, {{o.proctime between proctime() and
> proctime() + 1}} should also not be supported.
> This issue includes:
> * Design of the DataStream operator to deal with stream join
> * Translation from Calcite's RelNode representation (LogicalJoin).
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