SELECT that returns list of values not occurring in any row

If you don’t want to (explicitly) use temporary tables, this will work:

SELECT id FROM (
  (SELECT 1 AS id) UNION ALL
  (SELECT 2 AS id) UNION ALL
  (SELECT 3 AS id) UNION ALL
  (SELECT 4 AS id) UNION ALL
  (SELECT 5 AS id)
) AS list
LEFT JOIN users USING (id)
WHERE users.id IS NULL

However, it is quite ugly, quite long, and I am dubious about how it would perform if the list of IDs is long.