CREATE TABLE instructor (name VARCHAR2, id VARCHAR2, semester VARCHAR2)
CREATE TABLE teaches (name VARCHAR2, id VARCHAR2, semester VARCHAR2)

Find the names of instructors who didn't each any courses in any Spring semester.
SELECT name FROM instructor WHERE NOT id IN (SELECT id FROM teaches WHERE semester = 'Spring')
SELECT "name" FROM "instructor" WHERE NOT "id" IN (SELECT "id" FROM "teaches" WHERE "semester" = 'Spring')