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From lec ssmi <shicheng31...@gmail.com>
Subject Re: multiple joins in one job
Date Tue, 05 May 2020 08:42:06 GMT
But  I  have  not  found  there  is  any  syntax to  specify   time
 attribute  field  and  watermark  again  with  pure  sql.

Fabian Hueske <fhueske@gmail.com> 于 2020年5月5日周二 15:47写道:

> 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 is
>>>>>> 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 seems
>>>>>> 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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