Can you also provide the number of credits for each of those courses?
SELECT T1.credits,T1.course_id FROM course AS T1 JOIN prereq AS T2 ON T1.course_id   =   T2.course_id GROUP BY T2.course_id HAVING count ( * )   >  1
number of credits refers to T1.credits; for each of those courses refers to GROUP BY T2.course_id;