Viewing all unrelated records in a many-many relationship
At a seminar, STUDENTS can either attend or not attend any one of the SESSIONS offered. Their ATTENDANCE is recorded in a table linking the other two in a many-to-many relationship. I want to view the sessions with the students who attended them. I use the following relationship structure:
SESSIONS 1=∞ ATTENDANCE ∞=1 STUDENTS
I then create a layout based on SESSIONS with a portal showing related records from ATTENDANCE. The rows of that portal contain fields from STUDENTS. This setup lets me list every session with all the students who attended. My question is: how can I create a similar setup listing every session but this time with all the all the students who did not attend.
I tried to use the following relationship structure:
SESSIONS ∞≠∞ ATTENDANCE ∞=1 STUDENTS
but then I get a list of all the students who attended all the other sessions, which is irrelevant. Is there a way to achieve what I need ? I feel that I need to somehow reorganize the data and the tables, but I am not experienced enough to know even what direction to explore - any suggestion would be much appreciated.
More generally, what are the techniques to get all the unrelated records on the other side of a many-many relationship ?