题解 | 平均工资
平均工资
https://www.nowcoder.com/practice/95078e5e1fba4438b85d9f11240bc591
select avg(salary) as avg_salary from salaries where to_date = '9999-01-01' and salary not in (select max(salary) from salaries where to_date = '9999-01-01') and salary not in (select min(salary) from salaries where to_date = '9999-01-01');
