SET @start = '2016-11-28';
SET @end = '2016-11-30';
SELECT a.nomer
FROM allnomer a
LEFT JOIN main m
ON a.nomer = m.numbernomer
AND DATEDIFF(m.datestart, @end) * DATEDIFF(m.dateend, @start) <= 0
WHERE a.type = 'lux' AND m.numbernomer IS NULL
LIMIT 1