查找当前薪水排名第二多的员工，不使用order by完成

SELECT employees.emp_no, salaries.salary, employees.last_name, employees.first_name
FROM employees
JOIN salaries
ON employees.emp_no = salaries.emp_no
JOIN
    (SELECT MAX(salaries.salary) AS second_salary
    FROM salaries
    JOIN
        (SELECT MAX(salary) AS max_salary
        FROM salaries
        WHERE salaries.to_date='9999-01-01') AS max_s
    ON salaries.salary != max_s.max_salary
    WHERE salaries.to_date='9999-01-01') AS second_s
ON salaries.salary = second_s.second_salary
WHERE salaries.to_date='9999-01-01';