SELECT T1.emp_fname FROM employee AS T1 JOIN CLASS AS T2 ON T1.emp_num = T2.prof_num WHERE crs_code = 'CIS-220' INTERSECT SELECT T1.emp_fname FROM employee AS T1 JOIN CLASS AS T2 ON T1.emp_num = T2.prof_num WHERE crs_code = 'QM-261'
Temukan nama depan profesor yang mengajar dua kursus dengan Code CIS-220 dan QM-261.
CREATE TABLE CLASS (prof_num VARCHAR); CREATE TABLE employee (emp_fname VARCHAR, emp_num VARCHAR)