Performing left join between two streams

[Surendra Lalwani via user <us...@flink.apache.org>]

Hi Team,

Is it possible in Flink to perform Left Outer join between two streams as
it is possible in Spark. I checked for Internal join it only supports inner
join as of now.

Thanks and Regards ,
Surendra Lalwani

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Re: Performing left join between two streams

[Leonard Xu <xb...@gmail.com>]

Hi, Lalwani

Flink does not support outer join on two data streams now[1], you can use the DataStream API ds1.coGroup(ds2) as a workaround. Flink SQL support outer joins well, you can also try SQL way[2].
 

Best,
Leonard

[1] https://issues.apache.org/jira/browse/FLINK-4187
[2] https://nightlies.apache.org/flink/flink-docs-master/api/java/org/apache/flink/api/common/functions/CoGroupFunction.html
[2] https://nightlies.apache.org/flink/flink-docs-master/docs/dev/table/sql/queries/joins/#outer-equi-join <https://nightlies.apache.org/flink/flink-docs-master/docs/dev/table/sql/queries/joins/#outer-equi-join>


> 2022年10月28日 下午3:11，Surendra Lalwani via user <us...@flink.apache.org> 写道：
> 
> Hi Team,
> 
> Is it possible in Flink to perform Left Outer join between two streams as it is possible in Spark. I checked for Internal join it only supports inner join as of now.
> 
> Thanks and Regards ,
> Surendra Lalwani
> 
> 
> IMPORTANT NOTICE: This e-mail, including any attachments, may contain confidential information and is intended only for the addressee(s) named above. If you are not the intended recipient(s), you should not disseminate, distribute, or copy this e-mail. Please notify the sender by reply e-mail immediately if you have received this e-mail in error and permanently delete all copies of the original message from your system. E-mail transmission cannot be guaranteed to be secure as it could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or contain viruses. Company accepts no liability for any damage or loss of confidential information caused by this email or due to any virus transmitted by this email or otherwise.