Subject Firebird get the list with all available id
Author radubarbu84
In a table I have records with id's 2,4,5,8. How can I receive a list with values 1,3,6,7. I have tried in this way

SELECT t1.id + 1
FROM table t1
WHERE NOT EXISTS (
SELECT *
FROM table t2
WHERE t2.id = t1.id + 1
)

but it's not working correctly. It doesn't bring all available positions.

Is it possible without creating another table?