Could you please list each course's name and the number of its registered students?
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
What are the student ids of all students who registered for statistics?
select t2.student_id 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 where t3.course_name = 'statistics'
What are their student details, please?
select t1.student_details 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 where t3.course_name = 'statistics'