在SQLSERVER2005中实现素数计算

2022-07-15 80酷酷网 80kuku.com

　　server|sqlserver

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)