ТЕМА:

SELECT count(1) FROM INVENTORY
WHERE assigned_to IN
(SELECT employee_id
FROM employees
START WITH employee_id = '14998'
CONNECT BY PRIOR employee_id = supervisor_id);

select count(*) from inventory i

where exists (select null

              from employees e

              where i.assigned_to = e.employee_id

              connect by prior e.employee_id = e.supervisor_id

              start with employee_id = '14998')

;

SELECT count(1) FROM INVENTORY I,
(SELECT employee_id FROM employees
START WITH employee_id = '14998'
CONNECT BY PRIOR employee_id = supervisor_id) E
WHERE I.assigned_to = E.employee_id;