What is the name of the course that has the most student enrollment?
create table courses (course_name varchar, course_id varchar, PRIMARY KEY (course_name)); create table student_course_enrolment (course_id varchar, PRIMARY KEY (course_id))
select t1.course_name from courses as t1 join student_course_enrolment as t2 on t1.course_id = t2.course_id group by t1.course_name order by count(*) desc limit 1