_simon_ (2/1/2013)

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This is my scalar function, which returns numbers between @min-2 and @max-2 (both included):

create function GetRandom(@min int, @max-2 int)

returns int

as

begin

declare @diff int = @max-2 - @min-2 + 1

return @min-2 + crypt_gen_random(1) % @diff

end

This is how I test it:

-- This runs for about 50s on my computer.

declare @t table (Number int)

declare @winners table (Number int)

declare @i int = 0

declare @iCount int = 10

declare @j-2 int = 0

declare @jCount int = 100000

while (@i < @iCount)

begin

delete from @t

set @j-2 = 0

while (@j < @jCount)

begin

insert into @t (Number)

select dbo.GetRandom(1, 3)

set @j-2 += 1

end

insert into @winners (Number)

select top 1 Number

from (

select Number, count(*) C

from @t

group by Number

) x

order by C desc

set @i += 1

end

select Number, count(*)

from @winners

group by Number

order by count(*) desc

Output (number 1 wins in ~80% cases):

Number

----------- -----------

1 9

2 1

Now almost every time I run this query, the Number 1 appears slightly more often... Is there something wrong with my GetRandom function?