List the sum of employees' salaries grouped by department. (table EMPL)
SELECT deptno, SUM(sal) AS total_salary FROM EMPL GROUP BY deptno;
+--------+--------------+ | deptno | total_salary | +--------+--------------+ | 20 | 10885 | | 30 | 9400 | | 10 | 8750 | +--------+--------------+
