text: 
  
  select
  d.dept_no
  , d.dept_name
  , mgr.emp_no as mgr_emp_no
  , mgr.last_name as mgr_last_name
  , mgr.first_name as mgr_first_name
  , dm.from_date
  , dm.to_date
  from departments as d
  inner join dept_manager dm on dm.dept_no = d.dept_no
  inner join employees mgr on mgr.emp_no = dm.emp_no