declare @start date = '2016-12-12'; -- Новая дата заезда
declare @end date = '2016-12-20'; -- Новая дата выезда
declare @today date = '2016-12-11';
 
update  main
set     numbernomer = null
where   datestart > @today;
 
declare @mainnumber int;
 
while exists (select * from main where numbernomer is null)
begin
 
    select top(1) @mainnumber = id
    from    main
    where   numbernomer is null
    order by datestart asc, datediff(day, datestart, dateend) desc;
 
    update m0
    set     numbernomer = m1.nomer
    from    main m0
            cross apply (SELECT top 1 a.nomer
                        FROM    allnomer a
                                LEFT JOIN main m
                                ON a.nomer = m.numbernomer
                                AND DATEDIFF(day, m.datestart, m0.dateend) * DATEDIFF(day, m.dateend, m0.datestart) <= 0
                                left join (select m2.numbernomer, max(m2.dateend) as dateend from main m2 group by m2.numbernomer) as m2
                                        on a.nomer = m2.numbernomer
                        WHERE a.type = 'lux' AND m.numbernomer IS NULL
                        order by datediff(day, m2.dateend, m0.datestart), a.nomer
                        ) as m1
    where   m0.id = @mainnumber;
 
end;
 
SELECT a.nomer
FROM allnomer a
LEFT JOIN main m
  ON a.nomer = m.numbernomer
  AND DATEDIFF(day, m.datestart, @end) * DATEDIFF(day, m.dateend, @start) <= 0
WHERE a.type = 'lux' AND m.numbernomer IS NULL;