题解 | #平均工资#

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