generate seemingly random unique numeric ID in SQL Server

Question

I need to use SQL Server to generate seemingly random unique 8-digit numeric ID (can pad zeros at front). Is there a built-in functionality for this? I saw

Answer 1

 --create
--   table Tbl( idx int)
   DECLARE
   @unique_id int  

 SET @unique_id=  ( SELECT ROUND( 89999999 * RAND(
                                                   ) + 10000000 , 0
                                  )
                    )            
IF not EXISTS( SELECT idx
             FROM tbl
             WHERE idx = @unique_id
         )
    BEGIN
        INSERT INTO  tbl( idx
                               )
        VALUES( @unique_id
              )

SELECT @unique_id, * FROM tbl
    END;

    --TRUNCATE TABLE tbl