题解 | 统计各个部门平均薪资
统计各个部门平均薪资
https://www.nowcoder.com/practice/4722fdf89a4c43eebb58d61a19ccab31
select department, round(avg(normal_salary-dock_salary),3) avg_salary from staff_tb f join salary_tb s using(staff_id) where (normal_salary-dock_salary) between 4000 and 30000 group by department order by avg_salary desc; 这题就是先筛选后group了，用where
