Generate and Insert 1 million rows into simple table Description:

I try to insert 1 million rows into empty table on MSSQL 2012 Express. 
Here my script:

-- set statistics time off
drop table t1
create table t1 (id int, a text, b text) 
go

-- #1 - 1,000,000 - 30s -&gt; 45s
with ID(number) as
(
    select 1 as number
    union all
    select number + 1
    from ID
    where number &lt; 1000000 + 1
)
insert into t1
    select number, 'a_' + cast (number as varchar), 'b_' + cast (number/2 as varchar)
    from ID  
    option(maxrecursion 0)


-- #2 - 1 million rows =&gt; ~140,000 rows = 120s (have to cancel query)
declare @count int
set @count = 0
while @count &lt; 1000000
begin
    set @count = @count + 1
    insert into t1 
        values(@count, 'a_' + cast (@count as varchar), 'b_' + cast (@count/2 as varchar))
end

-- #3 - ~1,300,000 rows - 18s -&gt; 20s  

with temp as 
(
    SELECT  ROW_NUMBER() OVER(ORDER BY a.object_id) as tcount 
    from sys.all_columns a,  sys.all_columns b
    where a.object_id = b.object_id  
) 
insert into t1
    select tcount, 'a_' + cast (tcount as varchar), 'b_' + cast (tcount/2 as varchar) 
    from temp 
go

declare @count int
set @count = 0
while @count &lt; 3
begin
    with temp as (select max(id) + 1 as max_id from t1)
    insert into t1
        select max_id, 'a_' + cast (max_id as varchar), 'b_' + cast (max_id/2 as varchar) 
        from t1, temp 
    set @count = @count + 1
end

-- #4 -- 1,000,000 = 3s -&gt; 4s (have to drop t1 first)
with a(k) as
(
select 1 as k
union all
select k + 1 from a where k &lt; 99 + 1
) , 
t2 as (
select row_number() over(order by x.k) as k
from a x , a y , a z 
) 
select k as id , 'a_' + cast (k as varchar) as a, 'b_' + cast (k/2 as varchar) as b into t1
from t2


Question:

After researching , I found 4 solutions. Are there any better solution (not using copy data from files) ?
Itzik Ben-Gan uses following approach
This is probably the fastest way he found and he's quite smart :-)

WITH
  L0   AS (SELECT c FROM (SELECT 1 UNION ALL SELECT 1) AS D(c)), -- 2^1
  L1   AS (SELECT 1 AS c FROM L0 AS A CROSS JOIN L0 AS B),       -- 2^2
  L2   AS (SELECT 1 AS c FROM L1 AS A CROSS JOIN L1 AS B),       -- 2^4
  L3   AS (SELECT 1 AS c FROM L2 AS A CROSS JOIN L2 AS B),       -- 2^8
  L4   AS (SELECT 1 AS c FROM L3 AS A CROSS JOIN L3 AS B),       -- 2^16
  L5   AS (SELECT 1 AS c FROM L4 AS A CROSS JOIN L4 AS B),       -- 2^32
  Nums AS (SELECT ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) AS k FROM L5)

select k as id , 'a_' + cast (k as varchar) as a, 'b_' + cast (k/2 as varchar) as b into t1
from nums
where k &lt;= 1000000