มีใครยังไม่เคยสอน ENS 347 บ้าง ?ไม่จำเป็นต้องใช้ทุกตารางเลย
Is there anyone who has n't taught ENS 347 ?It is not neccessary to use all the tables.
 gsi:  course_offering_id [ int]  student_id [ int] 
SELECT DISTINCT name FROM instructor WHERE NOT name IN (SELECT INSTRUCTORalias1.name FROM course AS COURSEalias0 INNER JOIN course_offering AS COURSE_OFFERINGalias0 ON COURSEalias0.course_id = COURSE_OFFERINGalias0.course_id INNER JOIN offering_instructor AS OFFERING_INSTRUCTOR ON OFFERING_OFFERING_ID = COURSE_OFFERINGalias0.offering_id INNER JOIN instructor AS INSTRUCTORalias1 ON offering_instructor_id = INSTRUCTORalias1.instructor_id WHERE COURSEalias0.department = 'ENS' AND COURSEalias0.number = 347)