CREATE OR REPLACE TABLE EMPLOYEE (
  EMPID INT,
  DEPTID INT,
  SALARY DECIMAL(10,2)        
);
INSERT INTO EMPLOYEE VALUES(1,10,234.00);
INSERT INTO EMPLOYEE VALUES(2,10,1233.00);
INSERT INTO EMPLOYEE VALUES(3,20,600.00);
INSERT INTO EMPLOYEE VALUES(4,20,4512.00);
INSERT INTO EMPLOYEE VALUES(5,30,3424.00);
INSERT INTO EMPLOYEE VALUES(6,30,1232.00);
INSERT INTO EMPLOYEE VALUES(7,40,4445.00);
INSERT INTO EMPLOYEE VALUES(8,40,9999.00);
INSERT INTO EMPLOYEE VALUES(9,40,212000.00);

SELECT DEPTID
       ,SALARY
       ,ROW_NUMBER() OVER(PARTITION BY DEPTID ORDER BY SALARY DESC) AS RN
  FROM EMPLOYEE;