SELECT dept_name, first_name, last_name, emp_nr.employees
FROM (SELECT dept_name, d.dept_no, first_name, last_name
      FROM dept_manager dm
	      INNER JOIN employees e ON dm.emp_no = e.emp_no
	      INNER JOIN departments d ON d.dept_no = dm.dept_no
      WHERE dm.to_date >= current_date
      GROUP BY dept_no) AS manager
	INNER JOIN
	(
		SELECT dept_no, count(*) AS employees
		FROM current_dept_emp cde

		GROUP BY dept_no
	) AS emp_nr
		ON
			emp_nr.dept_no = manager.dept_no;