You did well, Marvin. Yes, that mdl versus prefix depends upon how you set up your tables, or if you are using Configurable Reports. You can also send the results to csv or Excel, then do anything that you wish.
Also, do some manual double-checking of your results from the query versus what you see in a few courses.
Also, do some manual double-checking of your results from the query versus what you see in a few courses.