【IT168 技术文档】

    我将提出一个挑战，谁能用SQLSEERVER提出计算素数最好的方法，我用了一个新的特点CTE和某些TSQL实现，但均不理想，前者（CTE）有限制，而后者（TSQL）产生一百万个素数用了7分种你可以干的更好么？这儿是我的一些代码段落

    （TSQL实现）

set nocount on
declare @prime table (prime int not null primary key)
--insert into @prime values (2) 
--insert into @prime values (3) 
--insert into @prime values (5) 
--insert into @prime values (7) 
--insert into @prime values (11) 
declare @number int, @pc int
set @number = 13
set @pc = 1
while @pc < 1000000
begin
if not exists (select 1 from @prime where @number % prime = 0 and prime < sqrt(@number) )
begin
insert into @prime select @number
set @pc = @pc +1
end
set @number = @number
+ case when @number %2 = 1 then 2
when @number %3 = 2 then 2
when @number %5 = 4 then 2
when @number %7 = 6 then 2
when @number %11 = 10 then 2
else 1 end
end
select @pc 

    和 （CTE实现）

with seq
as( select 13 number
union all
select s.number
+ case when s.number %2 = 1 then 2
when s.number %3 = 2 then 2
when s.number %5 = 4 then 2
when s.number %7 = 6 then 2
when s.number %11 = 10 then 2
else 1 end
from seq s
where number < 32767
)
, prime as (
select s.number
from seq s
where not exists ( select 1 from seq s2 where s2.number < s.number and (s.number) % s2.number = 0)
)
select * from prime option (MAXRECURSION 32767)