Намерете цялото дърво от корена, давайки произволен възел

Първо трябва да преминете нагоре по дървото, за да получите всички мениджъри, след което да преминете надолу, за да извлечете всички служители:

select level, employee_id, last_name, manager_id ,
       connect_by_root employee_id as root_id
   from employees
connect by prior employee_id = manager_id -- down the tree
start with manager_id in ( -- list up the tree
     select manager_id 
       from employees
     connect by employee_id = prior manager_id -- up the tree
     start with employee_id = 101
     )
;

Вижте http://www.sqlfiddle.com/#!4/d15e7/18

Редактиране:

Ако даденият възел може също да е основният възел, разширете заявката, за да включи дадения възел в списъка с родителски възли:

Пример за не-root възел:

select distinct employee_id, last_name, manager_id 
   from employees
connect by prior employee_id = manager_id -- down the tree
start with manager_id in ( -- list up the tree
     select manager_id 
       from employees
     connect by employee_id = prior manager_id -- up the tree
     start with employee_id = 101
     union 
     select manager_id -- in case we are the root node
       from employees
     where manager_id = 101
     )
;

Пример за основен възел:

select distinct employee_id, last_name, manager_id 
   from employees
connect by prior employee_id = manager_id -- down the tree
start with manager_id in ( -- list up the tree
     select manager_id 
       from employees
     connect by employee_id = prior manager_id -- up the tree
     start with employee_id = 100
     union 
     select manager_id -- in case we are the root node
       from employees
     where manager_id = 100
     )
;

Fiddle на http://www.sqlfiddle.com/#!4/d15e7/32