สำหรับคลาส RCIDIV 390 บ่อยแค่ไหน ?ไม่จำเป็นต้องใช้ตารางทั้งหมด
For class RCIDIV 390 , how often does it meet ?It is not neccessary to use all the tables.
 comment_instructor:  instructor_id [ int]  student_id [ int]  score [ int]  comment_text [ varchar] 
SELECT DISTINCT course_offering.friday, course_offering.monday, course_offering.saturday, course_offering.sunday, course_offering.thursday, course_offering.tuesday, course_offering.wednesday FROM course INNER JOIN course_offering ON course.course_id = course_offering.course_id INNER JOIN semester ON semester.semester_id = course_offering.semester WHERE course.department = 'RCIDIV' AND course.number = 390 AND semester.semester = 'WN' AND semester.year = 2016