Can you Please list all departments?
select dept_name from department
Thank You.  Can you provide the department code for each of these?
select distinct ( dept_code ) from department
Thank you.  Can you provide the names of students taking classes in CIS?
select t1.stu_fname, t1.stu_lname from student as t1 join enroll as t2 on t1.stu_num = t2.stu_num join class as t3 on t2.class_code = t3.class_code join course as t4 on t3.crs_code = t4.crs_code join department as t5 on t5.dept_code = t4.dept_code where t5.dept_name = 'Computer info. Systems'
Just the First name?
select t1.stu_fname from student as t1 join enroll as t2 on t1.stu_num = t2.stu_num join class as t3 on t2.class_code = t3.class_code join course as t4 on t3.crs_code = t4.crs_code join department as t5 on t5.dept_code = t4.dept_code where t5.dept_name = 'Computer info. Systems'
Which one of these students also has a class in ACCT?
select t1.stu_fname from student as t1 join enroll as t2 on t1.stu_num = t2.stu_num join class as t3 on t2.class_code = t3.class_code join course as t4 on t3.crs_code = t4.crs_code join department as t5 on t5.dept_code = t4.dept_code where t5.dept_name = 'Accounting' intersect select t1.stu_fname from student as t1 join enroll as t2 on t1.stu_num = t2.stu_num join class as t3 on t2.class_code = t3.class_code join course as t4 on t3.crs_code = t4.crs_code join department as t5 on t5.dept_code = t4.dept_code where t5.dept_name = 'Computer info. Systems'