题解 | #查找排除当前最大、最小salary之后的员工的平均工资avg_salary#

select avg(salary) from salaries
where salary > (select min(salary) from salaries where to_date = '9999-01-01')
and salary < (select max(salary) from salaries where to_date = '9999-01-01')
and to_date = '9999-01-01';