再帰CTEを使用して、ID番号の最小値と最大値の間のシーケンスを動的に生成することは、少し複雑なことを超える可能性がありますが、機能しているようです-
LIVE ON FIDDLE
CREATE TABLE tbl (
id VARCHAR(55)
);
INSERT INTO tbl VALUES
('AUTO_500'),
('AUTO_501'),
('AUTO_502'),
('AUTO_504'),
('AUTO_505'),
('AUTO_506'),
('AUTO_507'),
('AUTO_508'),
('509');
;WITH
data_cte(id)AS
(SELECT [id] = CAST(REPLACE(id, 'AUTO_', '') AS INT) FROM tbl)
,maxmin_cte(minId, maxId)AS
(SELECT [minId] = min(id),[maxId] = max(id) FROM data_cte)
,recursive_cte(n) AS
(
SELECT [minId] n from maxmin_cte
UNION ALL
SELECT (1 + n) n FROM recursive_cte WHERE n < (SELECT [maxId] from maxmin_cte)
)
SELECT x.n
FROM
recursive_cte x
LEFT OUTER JOIN data_cte y ON
x.n = y.id
WHERE y.id IS NULL