WITH RECURSIVE employee_recursive(distance, employee_name, manager_name) AS (
    SELECT 1, employee_name, manager_name
    FROM employee
    WHERE manager_name = 'Mary'
  UNION ALL
    SELECT er.distance + 1, e.employee_name, e.manager_name
    FROM employee_recursive er, employee e
    WHERE er.employee_name = e.manager_name
  )
SELECT distance, employee_name FROM employee_recursive;
---------------------------
WITH RECURSIVE employee_recursive (distance, employee_name, manager_name) AS (
		SELECT 1, employee_name, manager_name
		FROM employee
		WHERE manager_name = 'Mary'
		UNION ALL
		SELECT er.distance + 1, e.employee_name, e.manager_name
		FROM employee_recursive er, employee e
		WHERE er.employee_name = e.manager_name
	)
SELECT distance, employee_name
FROM employee_recursive;