Find rows that do not exist in a table by supplying literal values and without using a temporary table

gistfile1.sql

-- here's my table with some data in it
CREATE TABLE sample ( client_id INT );
INSERT INTO sample VALUES (1);

-- here's the challenge; if my app has values 1, 2, and 3, I want a query that returns '2' and '3'... i.e., all values not currently in the 'sample' table.  CTE to the rescue.

WITH app_client_ids(client_id) AS (VALUES(1), (2), (3)) 
SELECT client_ID from app_client_ids WHERE client_id NOT IN (SELECT client_id FROM sample);

-- result from psql:

 client_id 
-----------
         2
         3
(2 rows)