三层子查询 最里层用于查出最大的 第二层用于查出第二大的 最后一层用于组装数据

select
  e.emp_no,
  salaries.salary,
  e.last_name,
  e.first_name
from
  employees e,
  salaries,
  (
    select
      max(s.salary) as no2
    from
      (
        select
          max(salary) as no1
        from
          salaries
      ) t1,
      salaries s
    where
      s.salary != t1.no1
  ) as t2
 where salaries.salary = t2.no2 and e.emp_no = salaries.emp_no;