1、解法一,
第一步:找出工资的最大值和最小值
select max(salary) from salaries;
select min(salary) from salaries;第二步 计算工资不包含最大值和最小值的平均值
SELECT AVG(salary) as avg_salary from salaries where salary > (select min(salary) from salaries) and salary < (select max(salary) from salaries) and to_date='9999-01-01';2、解法二
平均值 = (sum(salary)-min(salary)-max(salary))/(count(1)-2)
select (sum(salary)-min(salary)-max(salary))/(count(1)-2) as svg_salary from salaries where to_date='9999-01-01';