A、SELECT * FROM emp_dept_vu;
B、SELECT department_id, SUM(salary) FROM emp_dept_vu GROUP BY department _ id;
C、SELECT department_id, job_id, AVG(salary) FROM emp_dept_vu GROUP BY department _ id, job_id;
D、SELECT job_id, SUM(salary) FROM emp_dept_vu WHERE department_id IN (10,20) GROUP BY job_id HAVING SUM (salary) > 20000
E、None of the statements produce an error; all are valid.