题解 | 获取当前薪水第二多的员工的emp_no以及其对应的薪水salary

select * from(
    select emp_no, salary, last_name, first_name from employees
    join salaries using(emp_no)
    where salary != (
        select max(salary) from salaries
    )
) as tb
where salary = (
    select max(salary) from (
        select emp_no, salary, last_name, first_name from employees
        join salaries using(emp_no)
        where salary != (
            select max(salary) from salaries
        )
    ) as tb1
)
#核心思想就是先剔除最大工资，再筛选剩下的最大工资（即第二大的工资记录）