CREATE TABLE course (title VARCHAR2, course_id VARCHAR2)
CREATE TABLE prereq (course_id VARCHAR2)

Find the title of courses that have two prerequisites?
SELECT T1.title FROM course AS T1 JOIN prereq AS T2 ON T1.course_id = T2.course_id GROUP BY T2.course_id HAVING COUNT(*) = 2
SELECT "T1"."title" FROM "course" "T1" JOIN "prereq" "T2" ON "T1"."course_id" = "T2"."course_id" GROUP BY "T2"."course_id" HAVING COUNT(*) = 2