CTE has limitation

CTE_not_fun.sql

--https://www.citusdata.com/blog/2018/05/15/fun-with-sql-recursive-ctes/
--Return: x
WITH RECURSIVE tens(x) AS (
	SELECT 10
	UNION
	SELECT x + 10 FROM tens WHERE x + 10 <= 100
)
SELECT x FROM tens;

--Without having to drop down to a procedural language like plpgsql or plv8.

--Ex.1
DROP TABLE employees;

CREATE TABLE employees (
  id 		 serial PRIMARY KEY,
  name 		 varchar(255),
  manager_id int
);

INSERT INTO employees VALUES (1, 'Umur', null);
INSERT INTO employees VALUES (2, 'Craig', 1);
INSERT INTO employees VALUES (3, 'Daniel', 2);
INSERT INTO employees VALUES (4, 'Claire', 1);
INSERT INTO employees VALUES (5, 'Lindsay', 2);
INSERT INTO employees VALUES (6, 'Will', 2);
INSERT INTO employees VALUES (7, 'Burak', 2);
INSERT INTO employees VALUES (8, 'Eren', 2);
INSERT INTO employees VALUES (9, 'Katie', 3);
INSERT INTO employees VALUES (10, 'Teresa', 4);

SELECT * FROM employees;

--No params
--Skip if manager_id is NULL
WITH RECURSIVE print_manager AS (
	SELECT id, name, manager_id FROM employees WHERE id = 2 --change to 3 :)
	UNION ALL
	SELECT e.id, e.name, e.manager_id 
	FROM employees e 
	INNER JOIN print_manager pm ON pm.id = e.manager_id   --can't be (outer) left join
)
SELECT id, "name", manager_id FROM print_manager;


WITH RECURSIVE print_manager AS (
	SELECT id, name, manager_id FROM employees WHERE id = 8
	UNION
	SELECT e.id, e.name, e.manager_id FROM employees e
	JOIN print_manager pm ON pm.id = e.manager_id    --future row start from 8th, won't contains any id = 2...so it stopped.
)
SELECT id, "name", manager_id FROM print_manager;