I’ve got students, courses, courseinstances(which includes ‘student_id’ and ‘course_id’ and whether they’ve passed), and a prerequisites table (‘course_id’ and ‘prereq_id’ both referencing courses). I wish to get the available courseinstances, concidering the necessary prerequisites and the fact that a course can’t be taken twice. I couldn’t find a way without recalculating some parts of theRead more