Re: How to create a solid sequence?

[Rick James]

I think this will (somewhat efficiently) find the first hole in tbl. And if there are no holes, find the next value off the end.

SELECT MIN(id)
    FROM (
        SELECT  a.id
            FROM tbl a
            LEFT JOIN tbl b  ON a.id = b.id+1
            WHERE b.id IS NULL
         ) AS x