Minecraft - Skyblock - Wave select/fill

SELECT
    IF(s.z = s.distance, s.x, s.x+s.z) AS a,
    s.distance
FROM
(
    SELECT
        sb.distance,
        sk.x,
        sk.z
    FROM
    (
        SELECT
            f.distance AS distance
        FROM
        (
            SELECT
                FLOOR(SQRT(x*x + z*z)) AS distance,
                COUNT(uuid) AS count,
                x,
                z
            FROM skyblock
            WHERE server='skyblock'
                AND type='void'
            GROUP BY floor(sqrt(x*x + z*z)) ASC
        ) AS f
        WHERE f.count != f.distance * 2 + 1
        LIMIT 1
    ) AS sb
    LEFT JOIN skyblock AS sk
        ON sk.server='skyblock'
            AND sk.type='void'
            AND floor(sqrt(sk.x*sk.x + sk.z*sk.z)) = sb.distance
) AS s
WHERE FLOOR(SQRT(s.x*s.x + s.z*s.z)) = s.distance
ORDER BY a