sql211
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 emp_no, salary
FROM salaries sa
WHERE salary = (
SELECT DISTINCT salary
FROM salaries
ORDER BY salary DESC
LIMIT 1,1
);
