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From Fabian Hueske <fhue...@gmail.com>
Subject Re: multiple joins in one job
Date Tue, 05 May 2020 07:47:00 GMT
Sure, you can write a SQL query with multiple interval joins that preserve
event-time attributes and watermarks.
There's no need to feed data back to Kafka just to inject it again to
assign new watermarks.

Am Di., 5. Mai 2020 um 01:45 Uhr schrieb lec ssmi <shicheng31604@gmail.com>:

> I mean using pure sql statement to make it . Can it be possible?
> Fabian Hueske <fhueske@gmail.com> 于2020年5月4日周一 下午4:04写道:
>> Hi,
>> If the interval join emits the time attributes of both its inputs, you
>> can use either of them as a time attribute in a following operator because
>> the join ensures that the watermark will be aligned with both of them.
>> Best, Fabian
>> Am Mo., 4. Mai 2020 um 00:48 Uhr schrieb lec ssmi <
>> shicheng31604@gmail.com>:
>>> Thanks for your replay.
>>> But as I known, if   the time attribute  will be retained and  the time
>>> attribute field  of both streams is selected in the result after joining,
>>> who is the final time attribute variable?
>>> Benchao Li <libenchao@gmail.com> 于2020年4月30日周四 下午8:25写道:
>>>> Hi lec,
>>>> AFAIK, time attribute will be preserved after time interval join.
>>>> Could you share your DDL and SQL queries with us?
>>>> lec ssmi <shicheng31604@gmail.com> 于2020年4月30日周四 下午5:48写道:
>>>>> Hi:
>>>>>    I need to join multiple stream tables  using  time interval join.
>>>>> The problem is that the time attribute will disappear  after the jon
, and
>>>>> pure  sql cannot declare the time attribute field again . So, to make
>>>>> success,  I need to insert  the last result of join to kafka ,and consume
>>>>> it and join it with another stream table  in another flink job . This
>>>>> troublesome.
>>>>> Any good idea?
>>>> --
>>>> Benchao Li
>>>> School of Electronics Engineering and Computer Science, Peking University
>>>> Tel:+86-15650713730
>>>> Email: libenchao@gmail.com; libenchao@pku.edu.cn

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