I'm trying to test your query but I'm getting error for invalid path. For source I copied and used the same path that I used for load and select statement for the main table. I even tried using the table name as source but still getting error.
Would you have any idea what could be causing the error?
If you want to load data from a database you need to create a connection to the database and to store these information within a lib. Usually it's helpful to create the (first shot of) the load-statement with the wizard.