Question

How can I write a single select statement that does the following:

I have an integer column in my table and i want to find the minimum available (non-used) value in that column where the value is below 1000 and also where the value does not exist in TableB Column1

Thanks

Answer 1

Similar to LukeH’s answer but it does what you asked for:

SELECT MIN(a.your_column) - 1 AS answer
FROM your_table AS a
LEFT JOIN your_table AS a2
        ON a2.your_column = a.your_column - 1
LEFT JOIN tableB AS b
        ON a.your_column = b.column1
WHERE a.your_column < 1000
    AND b.column1 IS NULL
    AND a2.your_column IS NULL

---

Edit:

UNION
SELECT MIN(a.your_column) + 1 AS answer
FROM your_table AS a
LEFT JOIN your_table AS a2
        ON a2.your_column = a.your_column + 1
LEFT JOIN tableB AS b
        ON a.your_column = b.column1
WHERE a.your_column < 1000
    AND b.column1 IS NULL
    AND a2.your_column IS NULL

And pick the minumum of the two values.

It still needs checking if the value 1 is available, but if you have a gap between A and B it should find A+1 and B-1 now and you could pick the smallest. Obviously A+1 is the smallest so you can just use the second part…