The Definitive Guide to Data Quality
Have you set up the join details in the tMap. eg inner join and linked the tables with the correct data item?
I can't get something as simple as a lookup to work. When I try to debug to see what may be going on, the trace for the lookup does not display. It also shows 2 rows in 0s with 0 rows/s. What the hell do I make of that? Is there some trick or secret that I don't know that I need to use to get the trace for the lookup to display? Look at GroupLkp in my image.
You've got left outer joins on your input tables. Click the spanner tool to expand the rules box.