T.DEPT_NO, T.DEPT_NAME, COUNT(DEPT_NO) OVER(PARTITION BY DEPT_NO) AS SN FROM ( SELECT T1.DEPT_NO, T1.DEPT_NAME, T3.SALARY FROM departments T1 LEFT JOIN dept_emp T2 ON T1.DEPT_NO = T2.DEPT_NO LEFT JOIN salaries T3 ON T2.EMP_NO = T3.EMP_NO )T ORDER BY T.DEPT_NO
