declare @t1 table (Id int)
insert into @t1 (Id)
select 1 union 
select 2 union 
select 3

declare @t2 table (Id int, X int)
insert into @t2 (Id, X)
select 1, 10 union
select 2, 5 union
select 3, 0

select 1 union all
select 1 union all
select 1 union all
select 1 union all
select 1 union all
select 1 union all
select 1 union all
select 1 union all
select 1 union all
select 1 union all
select 2 union all
select 2 union all
select 2 union all
select 2 union all
select 2

create function [dbo].[f_table_numbers] (@st bigint, @end bigint)
returns table
as
return
with
       a as (select convert(bigint,0) as n union all select 0),
       b as (select 0 as n from a as a cross join a as b),
       c as (select 0 as n from b as a cross join b as b),
       d as (select 0 as n from c as a cross join c as b),
       e as (select 0 as n from d as a cross join d as b),
       f as (select 0 as n from e as a cross join e as b),
       nums as (select row_number() over (order by (select 1)) as num from f as a cross join f as b)
select @st + num - 1 as num
from nums
where  num <= @end-@st+1

create function Temp (@Id int, @N int)
	returns @t table (Id int)
as
begin
	insert into @t (Id)
	select x.Id
	from (select @Id Id) x cross join (select Num from dbo.f_table_numbers(1, @N)) y

	return
end

declare @t1 table (Id int)
insert into @t1 (Id)
select 1 union select 2 union select 3

declare @t2 table (Id int, X int)
insert into @t2 (Id, X)
select 1, 10 union
select 2, 5 union
select 3, 0

;with temp as (
	select t1.Id, t2.X
	from @t1 t1 join @t2 t2 on (t1.Id = t2.Id)
)
select t1.Id
from temp t1 cross apply dbo.Temp(t1.Id, t1.X)

declare @t1 table (Id int)
insert into @t1 (Id)
select 1 union 
select 2 union 
select 3

declare @t2 table (Id int, X int)
insert into @t2 (Id, X)
select 1, 10 union
select 2, 5 union
select 3, 0;

with t3 as (
select id, x, row_number() over (partition by id order by id) ro from @t2
cross join sys.all_columns
)
select id, x from t3 where ro <= x

select t1.id
from @t1 t1
inner join @t2 t2 on t2.Id = t1.Id and t2.X > 0
cross apply (select top (t2.X) 1 from sys.columns) n(n)