SQLD(SQL 개발자) 기출 · 윈도우 함수

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1. 1.SELECT ENAME, SAL, DEPTNO,
   ROUND(PERCENT_RANK() OVER(PARTITION BY DEPTNO ORDER BY SAL) * 100, 2) AS SAL_RATIO
   FROM EMP E1
   ORDER BY DEPTNO, SAL DESC;
2. 2.SELECT E1.ENAME, E1.SAL, E1.DEPTNO,
   ROUND(E1.SAL/I.SUM_SAL * 100, 2) AS SAL_RATIO
   FROM EMP E1, (SELECT DEPTNO, SUM(SAL) AS SUM_SAL
   FROM EMP
   GROUP BY DEPTNO) I
   WHERE E1.DEPTNO = I.DEPTNO
   ORDER BY DEPTNO, SAL DESC;
3. 3.SELECT ENAME, SAL, DEPTNO,
   ROUND(RATIO_TO_REPORT(SAL) OVER(PARTITION BY DEPTNO) * 100, 2) AS SAL_RATIO
   FROM EMP E1
   ORDER BY DEPTNO, SAL DESC;
4. 4.SELECT ENAME, SAL, DEPTNO,
   ROUND(SAL/(SELECT SUM(SAL)
   FROM EMP E2
   WHERE E1.DEPTNO = E2.DEPTNO) * 100, 2) AS SAL_RATIO
   FROM EMP E1
   ORDER BY DEPTNO, SAL DESC;