#获取当前薪水第二多的员工的emp_no以及其对应的薪水
获取当前薪水第二多的员工的emp_no以及其对应的薪水salary
https://www.nowcoder.com/practice/8d2c290cc4e24403b98ca82ce45d04db
select s.emp_no,s.salary from salaries s where (select distinct salary from salaries order by salary desc limit 1,1) = s.salary order by emp_no;