SQL10 获取所有非manager的员工emp_no

问题

思路

方法1：NOT IN + 子查询
select emp_no
from employees
where emp_no not in (select emp_no from dept_manager);
方法2：LEFT JOIN左连接 + IS NULL
SELECT e.emp_no
FROM employees AS e
LEFT JOIN dept_manager AS d
ON e.emp_no=d.emp_no
WHERE dept_no IS NULL;