파티션 내 행에 고유 번호를 부여합니다.
문법
ROW_NUMBER() OVER (w)예제
아래 값을 입력하면 예제에 즉시 반영됩니다.
department_id→employee_id→salary→rank_in_dept→employees→SELECT department_id, employee_id, salary,
ROW_NUMBER() OVER (PARTITION BY department_id ORDER BY salary DESC) AS rank_in_dept
FROM employees;