set dateformat dmy

declare @td table (d date)
declare @d datetime = '2017-01-01'

while @d <= '2018-01-10'
begin
insert @td (d) select @d
set @d = dateadd(dd,1,@d)
end

-------------------------------------------------------------------------

declare @tt_sku table
( codett varchar (8), sku int, datestart date, dateend date) 

insert into @tt_sku select 'tt1', 00001,'01.10.2017', '10.10.2017'
insert into @tt_sku select 'tt1', 00002,'01.10.2017', '10.10.2017'
insert into @tt_sku select 'tt2', 00001,'08.10.2017', '16.10.2017'
insert into @tt_sku select 'tt2', 00002,'08.10.2017', '16.10.2017'

select
*
from
@tt_sku t
outer apply
(select d as istart, dateadd(dd,6,td.d) as iend from @td td where td.d >= datestart and dateadd(dd,6,td.d) <= dateend) f