/* 4. */
SELECT first_name, last_name
FROM employees
JOIN dept_emp ON dept_emp.emp_no=employees.emp_no
WHERE dept_no=(
	SELECT max_emps_tbl.dept_no
	FROM (
		/*  3. */
		SELECT departments.dept_no, COUNT(*) AS nr
		FROM departments
		JOIN dept_emp ON departments.dept_no=dept_emp.dept_no
		GROUP BY dept_no
		HAVING nr=(
			/* 2. retrieves the maximum value of the nr_of_emps column */
			SELECT MAX(dept_emp_summary.nr_of_emps) AS max_emps
			FROM (
				/* 1.: creates a summary of departments and the number of employees*/
				SELECT departments.dept_no, COUNT(*) AS nr_of_emps
				FROM departments
				JOIN dept_emp ON departments.dept_no=dept_emp.dept_no
				GROUP BY dept_no)
			AS dept_emp_summary))
	AS max_emps_tbl
)