More on primes

I've changed my algorithm a bit, so that it starts with the low-hanging fruit.

insert into dbo.rf_primesfound (num)
select 2 union all
select 3 union all
select 5 union all
select 7 union all
select 11 union all
select 13 union all
select 17 union all
select 19 union all
select 23 union all
select 29 union all
select 31;

DECLARE @BigLimit int;
SET @BigLimit = 1000000;

DECLARE @Limit int;
SET @Limit = 32;
DECLARE @OldLimit int;
SET @OldLimit = 32;

DECLARE @Start datetime, @End datetime;
SET @Start = CURRENT_TIMESTAMP;

while @limit < @BigLimit
begin
select @Oldlimit = @limit, @limit = @limit * @limit;
if @limit > @BigLimit set @limit = @BigLimit;

insert into dbo.rf_primesfound
select p.num
from dbo.nums n1
join
dbo.rf_primesfound f
on n1.num between 2 and @limit / f.num
right join
dbo.nums p
on p.num = f.num * n1.num
where f.num is null
and p.num > @Oldlimit
and p.num <= @limit;

end

SET @End = CURRENT_TIMESTAMP

SELECT @Start AS Start_time, @End AS End_time,
DATEDIFF(ms, @Start, @End) AS Duration,
COUNT(*) AS Primes_found, @Limit AS Limit
FROM dbo.rf_primesfound

select * from dbo.rf_primesfound

This gets down to 7 seconds, which isn't quite as good as Ward's 5. I do wonder what other improvements I could make, but I have a few other things to sort out this weekend (like my talk for the SQL Code Camp next weekend).