Is it possible to use multiple left join in Confluent KSQL query? tried to join stream with more than 1 tables , if not then whats the solution?

Question

Stream :

describe ammas;

 Field   | Type                        
-------------------------------------  
 ROWTIME | BIGINT           (system)  
 ROWKEY  | VARC         


        

Answer 1

KSQL currently (v5.3) only supports a single join operation per statement. If you want to perform multiple joins you have to "daisy-chain" them in multiple statements, e.g.

CREATE STREAM out1 AS 
  SELECT * FROM ammas cd 
           LEFT JOIN appat ab 
             ON ab.id = cd.id 

CREATE STREAM out_final AS 
  SELECT * FROM out1 o 
           LEFT JOIN annat aa ON o.id =cd.id;

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Update November 2020: ksqlDB supports multi-way joins were added in ksqlDB v0.9. Confluent Platform 6.0 includes ksqlDB 0.10.2 and therefore also includes this functionality. See the release blog and documentation for details.