What are the course descriptions?
select crs_description from course
Also, show credits.
select crs_description, crs_credit from course
Which of the above refer to courses that a student with the last name 'Smithson' took?
select t4.crs_description, t4.crs_credit 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 join course as t4 on t4.crs_code = t1.crs_code where t3.stu_lname = 'Smithson'