Average across matching records
OK, this is probably a real dumb question, but I have been working on databases all day long, and my brain has turned to mush.
I have a database with student records. Related to this database are several tables with student grades, (one for each subject...long story as to why, but it works for what we need it to do). Most of the time students only have one grade per subject, but for a couple of subjects, students have two or more grades. For what we are using our database for, I need to be able to get an average of the grades within each table (subject) for each student. Is there a simple way to do this that I am totally missing?