Which professors are teaching some classes?
select * from class as t1 join employee as t2 on t1.prof_num = t2.emp_num join professor as t3 on t2.emp_num = t3.emp_num
Which of them are from the Computer Information Systems department?
select * from class as t1 join employee as t2 on t1.prof_num = t2.emp_num join professor as t3 on t2.emp_num = t3.emp_num join department as t4 on t4.dept_code = t3.dept_code where t4.dept_name = 'Computer info. Systems'
What are their first names and highest degrees?
select distinct t2.emp_fname, t3.prof_high_degree from class as t1 join employee as t2 on t1.prof_num = t2.emp_num join professor as t3 on t2.emp_num = t3.emp_num join department as t4 on t4.dept_code = t3.dept_code where t4.dept_name = 'Computer info. Systems'