Merging a stream with table input records NOT in the stream

Question

I am trying to pull together a complex Kettle transformation on a set of patient data. I have several table input steps that query a MySQL table that assembles patient rows into a stream. Each table input step appends a "patient stage" column (e.g. "PreOpScheduled" and "PostOpScheduled").

Now I need to select all the rows of the patient table that are not part of the other table input steps and set the patient stage column to "Active". These rows need to be appended to the stream for further processing.

"Select from patient where not in patient stage stream"

Answer 1

just use a merge join step, and do an outer join, and some row filtering after that.