Find all information on students.
select * from student
Which of that information refers to people with the last name Smithson?
select * from student where stu_lname = 'Smithson'
What are the codes of the courses they took?
select t1.crs_code from class as t1 join enroll as t2 on t1.class_code = t2.class_code join student as t3 on t3.stu_num = t2.stu_num where t3.stu_lname = 'Smithson'