ใครเป็นคนสอน MICRBIOL 320 ในช่วงฤดูใบไม้ผลิ ?ไม่จำเป็นต้องใช้โต๊ะทั้งหมด
Who is teaching MICRBIOL 320 in the Spring ?It is not neccessary to use all the tables.
 comment_instructor:  instructor_id [ int]  student_id [ int]  score [ int]  comment_text [ varchar] 
SELECT DISTINCT instructor.name FROM course INNER JOIN course_offering ON course.course_id = course_offering.course_id INNER JOIN offering_instructor ON offering_instructor.offering_id = course_offering.offering_id INNER JOIN instructor ON offering_instructor.instructor_id = instructor.instructor_id INNER JOIN semester ON semester.semester_id = course_offering.semester WHERE course.department = 'MICRBIOL' AND course.number = 320 AND semester.semester = 'Spring' AND semester.year = 2016