题解 | #平均工资#
平均工资
http://www.nowcoder.com/practice/95078e5e1fba4438b85d9f11240bc591
select avg(salary) avg_salary
from salaries
where 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')
and to_date = '9999-01-01';