But I do it little bit differently

#Select all managers' first and last name, hire date, job title, start date, and department name.

select 
 dm.emp_no,
    e.first_name,
 e.last_name,
    e.hire_date,
    t.title,
    dm.from_date,
    d.dept_name
FROM 
employees e
 JOIN 
 dept_manager dm ON e.emp_no = dm.emp_no
 JOIN 
 departments d ON dm.dept_no = d.dept_no 
 JOIN 
 titles t ON t.emp_no = e.emp_no
WHERE 
t.title = "Manager";