Sorry, I forgot to CC the user mailing list in my reply.

2018-04-12 17:27 GMT+02:00 Fabian Hueske <fhue...@gmail.com>:

> Hi,
>
> Assuming you are using event time, the right function to generate a row
> time attribute from a window would be "w1.rowtime" instead of "w1.start".
>
> The reason why Flink is picky about this is that we must ensure that the
> result rows of the windows are aligned with the watermarks of the stream.
>
> Best, Fabian
>
>
> Ivan Wang <ivan.wang2...@gmail.com> schrieb am So., 8. Apr. 2018, 22:26:
>
>> Hi all,
>>
>>
>>
>> I'd like to use 2 window group in a chain in my program as below.
>>
>>
>>
>> Table myTable = cTable
>>         .window(Tumble.*over*("15.seconds").on("timeMill").as("w1"))
>>         .groupBy("symbol, w1").select("w1.start as start, w1.end as end,
>> symbol, price.max as p_max, price.min as p_min")
>>         .window(Slide.*over*("150.rows").every("1.rows").on("start").as(
>> "w2"))
>>         .groupBy("symbol, w2").select("w2.start, w2.end, symbol,
>> p_max.max, p_min.min")
>>         ;
>>
>>
>>
>>
>>
>> However, it throws error: SlidingGroupWindow('w2, 'start, 150.rows,
>> 1.rows) is invalid: Sliding window expects a time attribute for grouping in
>> a stream environment.
>>
>>          at org.apache.flink.table.plan.logical.LogicalNode.
>> failValidation(LogicalNode.scala:149)
>>
>>          at org.apache.flink.table.plan.logical.WindowAggregate.
>> validate(operators.scala:658)
>>
>>          at org.apache.flink.table.api.WindowGroupedTable.select(
>> table.scala:1159)
>>
>>          at org.apache.flink.table.api.WindowGroupedTable.select(
>> table.scala:1179)
>>
>>          at minno.gundam.ReadPattern.main(ReadPattern.java:156)
>>
>>
>>
>> Is there any way to assign time attribute after the first groupBy (w1)?
>>
>>
>>
>> Thanks
>>
>> Ivan
>>
>>
>>
>>

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