I'm using the QueryRecord processor in Apache NiFi to perform a LEFT JOIN between two sets of records within a single FlowFile. The records are distinguished by a field m, where m = 'a' represents one dataset and m = 'b' represents the other. Here is the SQL query I'm using: SELECT * FROM ( SELECT * FROM FLOWFILE WHERE m = 'a' ) file1 LEFT JOIN ( SELECT * FROM FLOWFILE WHERE m = 'b' ) file2 ON file1.ID = file2.rapid_id However, the result only includes records from the m = 'a' side. When I switch the inner queries (i.e., use m = 'b' as the left side), I only get records from that side instead. It seems the LEFT JOIN is not functioning as expected — it behaves more like an INNER JOIN. Has anyone encountered this behavior with QueryRecord? Is there a limitation in how it handles subqueries or joins within a single FlowFile? Any guidance or workaround would be appreciated. Thanks in advance!   ... View more