For each course id, how many students are registered and what are the course names?
SELECT T3.course_name ,  count(*) FROM students AS T1 JOIN student_course_registrations AS T2 ON T1.student_id = T2.student_id JOIN courses AS T3 ON T2.course_id = T3.course_id GROUP BY T2.course_id
Her ders kimliği için kaç öğrenci kayıtlıdır ve kurs isimleri nelerdir?