Put both tables in Kafka topics and have SQL Stream Builder joing them with a simple SQL Join.   or https://community.cloudera.com/t5/Support-Questions/Nifi-how-to-sql-join-two-flowfiles/td-p/298227   http://apache-nifi-users-list.2361937.n4.nabble.com/Joining-two-or-more-flow-files-and-merging-the-content-td10543.html   https://medium.com/@surajnagendra/merge-csv-files-apache-nifi-21ba44e1b719   ... View more

thank you very much Mr. Shelton ... View more

Dont know if it is the best solution, but if you know the keys of the JSON, you can use the Processor 'EvaluateJsonPath' and put the values as attribute to the flowfile. Then use Processor 'AttributsToJson' and set the JSON key and the value with expression language ${attr:trim()} ... View more