WITH
RECURSIVE Ids AS (
SELECT 1 AS id
UNION ALL
SELECT id + 1
FROM Ids
WHERE id < (
SELECT MAX(customer_id)
FROM Customers
)
)
SELECT Ids.id AS ids
FROM Ids
LEFT JOIN Customers
ON (Ids.id = Customers.customer_id)
WHERE Customers.customer_id IS NULL
ORDER BY 1;
¶
