ในฤดูใบไม้ร่วงปี 2017 มีศาสตราจารย์กี่คนที่จะสอน MICRBIOL 995 ?ไม่จำเป็นต้องใช้ตารางทั้งหมด
In the Fall of 2017 how many professors will teach MICRBIOL 995 ?It is not neccessary to use all the tables.
 program_requirement:  program_id [ int]  category [ varchar]  min_credit [ int]  additional_req [ varchar] 
SELECT COUNT(DISTINCT instructor.instructor_id) FROM course, course_offering, instructor, offering_instructor, semester WHERE course.course_id = course_offering.course_id AND course.department = 'MICRBIOL' AND course.number = 995 AND offering_instructor.instructor_id = instructor.instructor_id AND offering_instructor.offering_id = course_offering.offering_id AND semester.semester = 'Fall' AND semester.semester_id = course_offering.semester AND semester.year = 2017