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https://issues.apache.org/jira/browse/FLINK-6233?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16094719#comment-16094719
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Xingcan Cui commented on FLINK-6233:
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[~fhueske], thanks for the explanation. It' quite clear.
There's another two questions.
# I remember that the timestamp field is defined when creating the Table, e.g.,
{{stream.toTable(tEnv, 'long.rowtime, 'int, 'string)}}. Do we have any plan on
how to assign a new timestamp field? Let's say we have the following query:
{code:java}
// Table left: [a, b, ltime]
// Table right: [c, d, rtime]
SELECT a, b, ltime, c, rtime
FROM left, right
WHERE a = c AND ltime BETWEEN rtime - INTERVAL '1' HOUR AND rtime + INTERVAL
'1' HOUR
{code}
What should be done if I want to use {{ltime}} as the timestamp field of the
result?
# For a joined result, we can "synchronize" their timestamps just like the
{{AbstractStreamOperator}}. How about an aggregated result that is generated
from a window?
> Support rowtime inner equi-join between two streams in the SQL API
> ------------------------------------------------------------------
>
> Key: FLINK-6233
> URL: https://issues.apache.org/jira/browse/FLINK-6233
> Project: Flink
> Issue Type: Sub-task
> Components: Table API & SQL
> Reporter: hongyuhong
> Assignee: Xingcan Cui
>
> 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.rowtime , o.productId, o.orderId, s.rowtime AS shipTime
> FROM Orders AS o
> JOIN Shipments AS s
> ON o.orderId = s.orderId
> AND o.rowtime BETWEEN s.rowtime AND s.rowtime + 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.rowtime BETWEEN s.rowtime AND s.rowtime + INTERVAL
> '1' HOUR}} only can use rowtime that is a system attribute, the time
> condition only support bounded time range like {{o.rowtime BETWEEN s.rowtime
> - INTERVAL '1' HOUR AND s.rowtime + INTERVAL '1' HOUR}}, not support
> unbounded like {{o.rowtime < s.rowtime}} , and should include both two
> stream's rowtime attribute, {{o.rowtime between rowtime () and rowtime () +
> 1}} should also not be supported.
> An row-time streams join will not be able to handle late data, because this
> would mean in insert a row into a sorted order shift all other computations.
> This would be too expensive to maintain. Therefore, we will throw an error if
> a user tries to use an row-time stream join with late data handling.
> This issue includes:
> * Design of the DataStream operator to deal with stream join
> * Translation from Calcite's RelNode representation (LogicalJoin).
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