Tell me all the enrollment information for the student with personal name "Else".
select * from student_course_enrolment as t1 join students as t2 on t1.student_id = t2.student_id where t2.personal_name = "Else"
How about that for the personal name "Wilson"?
select * from student_course_enrolment as t1 join students as t2 on t1.student_id = t2.student_id where t2.personal_name = "Wilson"
Tell me the student ID and middle name for all the students with at most two enrollments.
select t1.student_id, t2.middle_name from student_course_enrolment as t1 join students as t2 on t1.student_id = t2.student_id group by t1.student_id having count(*) <= 2