List the id of students who registered course statistics in the order of registration date.
create table student_course_registrations (student_id varchar, course_id varchar, registration_date varchar, PRIMARY KEY (student_id)); create table courses (course_id varchar, course_name varchar, PRIMARY KEY (course_id))
select t2.student_id from courses as t1 join student_course_registrations as t2 on t1.course_id = t2.course_id where t1.course_name = "statistics" order by t2.registration_date