I'd like to know about the prerequisites for courses
select course_id, prereq_id from prereq
What courses have more than one prerequisite?
select course_id from prereq group by course_id having count ( * ) > 1
What are the title, credit and department of these courses?
select t1.title, t1.credits, t1.dept_name from course as t1 join prereq as t2 on t1.course_id = t2.course_id group by t2.course_id having count ( * ) > 1
Game programming
select sum ( t3.credits ) from course as t1 join prereq as t2 on t1.course_id = t2.course_id join course as t3 on t3.course_id = t2.prereq_id where t1.title = "Game Programming"