-- Alphanumeric key generator

-- Sequence table
CREATE TABLE Sequence (i INT NOT NULL IDENTITY(0,1) PRIMARY KEY);
GO
-- Encode function
CREATE FUNCTION dbo.EncodeInt(@i INTEGER)
RETURNS CHAR(8)
AS 
 BEGIN;
 RETURN
  SUBSTRING('ABCDEFGHIJKLMNOPQRSTUVWXYZ',FLOOR(@i/9/9/9/9/26/26/26)%26+1 ,1)+
  SUBSTRING('ABCDEFGHIJKLMNOPQRSTUVWXYZ',FLOOR(@i/9/9/9/9/26/26)%26+1 ,1)+
  SUBSTRING('ABCDEFGHIJKLMNOPQRSTUVWXYZ',FLOOR(@i/9/9/9/9/26)%26+1 ,1)+
  SUBSTRING('ABCDEFGHIJKLMNOPQRSTUVWXYZ',FLOOR(@i/9/9/9/9)%26+1 ,1)+
  SUBSTRING('123456789',FLOOR(@i/9/9/9)%9+1 ,1)+
  SUBSTRING('123456789',FLOOR(@i/9/9)%9+1 ,1)+
  SUBSTRING('123456789',FLOOR(@i/9)%9+1 ,1)+
  SUBSTRING('123456789',@i%9+1 ,1)
 END
 GO
 -- Next value function
 CREATE PROC GetNextValue
  (@pV CHAR(8) OUTPUT)
 AS
  SET NOCOUNT ON;
  DECLARE @i INT;

  BEGIN TRAN;
   INSERT INTO dbo.Sequence DEFAULT VALUES;
  ROLLBACK TRAN;

  SET @i = SCOPE_IDENTITY();
  SET @pV = dbo.EncodeInt(@i);
GO

-- Test it
DECLARE @v CHAR(8);
EXEC GetNextValue @pV = @v OUT ;
PRINT @v;