/****************************
This function converts an int 
using a supplied base
****************************/
Create Function dbo.intToBase
(
	@n bigint,	
	@base varchar(1000)
)
Returns varchar(1000) As
Begin
	Declare @baseNum int
	Set @baseNum = len(@base)

	Declare @code varchar(1000)

	while (@n>0)
		Select @code=substring(@base,@n%@baseNum+1,1)+isnull(@code,''), @n=@n/@baseNum

	Return @code
End
Go
/****************************
This function converts a base- 
converted value to the original 
int using a supplied base
****************************/
Create Function dbo.baseToInt
(
	@code varchar(1000),	
	@base varchar(1000)
)
Returns bigint As
Begin
	Declare @baseNum int
	Set @baseNum = len(@base)

	Declare @n bigint
	Select @n = charindex(left(@code,1) Collate Latin1_General_CS_AS_KS_WS,@base Collate Latin1_General_CS_AS_KS_WS)-1, @code=right(@code,len(@code)-1)

	While (len(@code)>0)
		Select @n=(@n*@baseNum)+charindex(left(@code,1) Collate Latin1_General_CS_AS_KS_WS,@base Collate Latin1_General_CS_AS_KS_WS)-1, @code=right(@code,len(@code)-1)

	Return @n
End
Go

Declare @n bigint,
	@n2 bigint,
	@base varchar(1000),
	@code varchar(100)

-- This uses the full datetime (yyyymmddhhnnmmmm) but in reverse to get greater variation in the resulting base
Set @n = convert(bigint,reverse(dbo.getCharacters(convert(varchar,getdate(),121),'0-9')))

Set @base = '0123456789bcdfghjkmnopqrstuvwxyzBCDFGHJKLMNPQRTVWXYZ'
Set @code = dbo.intToBase(@n,@base)
Set @n2 = dbo.baseToInt(@code,@base)

Select base=@base, n=@n, baseFromN=@code, nFromBase=@n2
Go

Drop Function dbo.intToBase
Drop Function dbo.baseToInt

/*********************************
Removes any characters from 
@myString that do not meet the 
provided criteria.
*********************************/
CREATE FUNCTION dbo.GetCharacters(@myString varchar(500), @validChars varchar(100))
RETURNS varchar(500) AS
BEGIN
 
	While @myString like '%[^' + @validChars + ']%'
		Select @myString = replace(@myString,substring(@myString,patindex('%[^' + @validChars + ']%',@myString),1),'')

	Return @myString
END
Go