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

1、题目描述

查找排除当前最大、最小salary之后的员工的平均工资avg_salary。
CREATE TABLE `salaries` ( `emp_no` int(11) NOT NULL,
`salary` int(11) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`from_date`));
输出格式:

avg_salary

69462.5555555556

2、代码

select avg(salary) as avg_salary from salaries
where to_date = '9999-01-01'
and salary not in (select min(salary) from salaries)
and salary not in (select max(salary) from salaries);