1、查询部门经理的编号
select emp_no from dept_manager2、查询部门经理的薪水
select c.emp_no as manager_no,c.dept_no,d.salary as manager_salary from dept_emp c join salaries d on c.emp_no=d.emp_no where c.emp_no in (select emp_no from dept_manager)3、查询普通员工的薪水
select a.emp_no,a.dept_no,b.salary as emp_salary from dept_emp a join salaries b on a.emp_no=b.emp_no where a.emp_no not in (select emp_no from dept_manager)4、将2表和3表连接,查询普通员工薪水大于经理薪水的信息
select e.emp_no,f.manager_no,e.emp_salary,f.manager_salary from (select a.emp_no,a.dept_no,b.salary as emp_salary from dept_emp a join salaries b on a.emp_no=b.emp_no where a.emp_no not in (select emp_no from dept_manager)) e join (select c.emp_no as manager_no,c.dept_no,d.salary as manager_salary from dept_emp c join salaries d on c.emp_no=d.emp_no where c.emp_no in (select emp_no from dept_manager)) f on e.dept_no=f.dept_no where e.emp_salary>f.manager_salary;