ชีววิทยา 281 สอนโดยใคร ?ไม่จำเป็นต้องใช้ตารางทั้งหมด
By whom is BIOLOGY 281 taught ?It is not neccessary to use all the tables.
 program:  program_id [ int]  name [ varchar]  college [ varchar]  introduction [ varchar] 
SELECT DISTINCT instructor.name FROM course, course_offering, instructor, offering_instructor WHERE course.course_id = course_offering.course_id AND course.department = 'BIOLOGY' AND course.number = 281 AND offering_instructor.instructor_id = instructor.instructor_id AND offering_instructor.offering_id = course_offering.offering_id