RANK 함수
RANK 함수: 순위 결정
RANK() OVER(ORDER BY sal DESC)
※ DESC가 생략되면 ASC
SELECT ename,sal,deptno,RANK() OVER(ORDER BY sal DESC) AS rank FROM emp;
SELECT ename,sal,deptno,RANK() OVER(ORDER BY sal DESC) AS rank FROM emp WHERE deptno=10;
SELECT ename,sal,deptno,RANK() OVER(ORDER BY sal DESC) AS rank FROM emp WHERE deptno=20;
SELECT ename,sal,deptno,RANK() OVER(ORDER BY sal DESC) AS rank FROM emp WHERE deptno=30;
SELECT ename,sal,deptno,RANK() OVER(PARTITION BY deptno ORDER BY sal DESC) AS rank FROM emp;