OBJEDNÁVKA MYSQL UNION

Budete muset zavést umělý klíč řazení. Něco jako:

SELECT
    *, 1 as SortKey
FROM 
    Devices
WHERE
    Live = 'true'
    AND Category = 'apple'
UNION
SELECT
        *, 2 as SortKey
    FROM
        Devices
    WHERE
        DeviceLive = 'true'
ORDER BY SortKey, ListOrder