薪水第二多的员工

SELECT s1.emp_no, s1.salary
FROM salaries AS s1
JOIN
    (SELECT salary
    FROM salaries
    WHERE to_date='9999-01-01'
    GROUP BY salary
    ORDER BY salary DESC
    LIMIT 1 OFFSET 1) AS s2
ON s1.salary = s2.salary
WHERE to_date='9999-01-01';