SELECT last_name, first_name, dept_no FROM employees AS e LEFT JOIN dept_emp AS de ON e.emp_no = de.emp_no
使用左连接,以employees表作为基础表,可以将所有员工的部门进行显示(没有部门的员工部门为NULL)
SELECT last_name, first_name, dept_no FROM employees AS e LEFT JOIN dept_emp AS de ON e.emp_no = de.emp_no