编写计算n!(n=30)的SQL语句，并显示计算结果。

declare @product real
declare @n smallint
declare @start smallint
declare @nflag smallint
set @start=1
set @n=30
set @nflag=@start
set @product=@start

begin
while @nflag<=@n
begin
set @nflag=@nflag + 1
set @product=@product * @nflag
end
select '结果为： ',@product,str(@product,40)
end

declare @n int , @t decimal(38,0)
set @n=1
set @t=1
while (@n<=30)
begin
set @t=@t*@n
set @n=@n+1
end
print @t
----------------------------
265252859812191058636308480000000