使用分析函数解题部分答案里的group by用法很不规范。select t.dept_no,t.emp_no,t.salary from(select de.dept_no,de.emp_no,s.salary,row_number() over(partition by de.dept_no order by s.salary desc) as rkfrom (select * from dept_emp where to_date='9999-01-01') deinner join(select * from salaries where to_date='9999-01-01') so...