, >=, =, (!=를 의미)WHERE salary > 70000BETWEEN A AND BWHERE salary BETWEEN 900 AND 1000Tuple comparisonWHERE (instruction.ID, dept_name) = (teahces.ID, 'Biology');IS NULLWHERE salary IS NULLIS NOT NULLWHERE salary IS NOT NULLSETUNION(SELECT course_id FROM teahces WHERE semester = 'Fall' AND year 2017)UNION(SELECT course_id FROM teahces WHERE semester = 'Spring' AND year 2018)INTERSECT -> 교집합SELECT..