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 st.department ,round(avg(sa.normal_salary-sa.dock_salary),3) as avg_salary from staff_tb st join salary_tb sa on st.staff_id = sa.staff_id where sa.normal_salary-sa.dock_salary between 4000 and 30000 group by st.department order by avg_salary desc