DECLARE @RoutingNumber VARCHAR(8000) --Allows check of wrong size numbers
    SET @RoutingNumber = '067803457'

 SELECT CASE
        WHEN LEN(@RoutingNumber)=9
         AND @RoutingNumber NOT LIKE '%[^0-9]%' --Check to make sure is all digits
         AND RIGHT(@RoutingNumber ,1)
           = (--==== Calculates check digit (Digit 9)
              SELECT 10-SUM(mv.DigitVal)%10 --Sum of individual digit values subtracted for new number ending in 0
                FROM (--==== Gets multiplied value for each digit in 3, 7, 1 pattern
                      SELECT CASE 
                             WHEN (t.N-1)%3 = 0 THEN SUBSTRING(@RoutingNumber,t.N,1)*3 --Digits 1,4,7
                             WHEN (t.N-1)%3 = 1 THEN SUBSTRING(@RoutingNumber,t.N,1)*7 --Digits 2,5,8
                             WHEN (t.N-1)%3 = 2 THEN SUBSTRING(@RoutingNumber,t.N,1)*1 --Digits 3,6
                             END AS DigitVal
                        FROM dbo.Tally t --See http://www.sqlservercentral.com/scripts/Advanced+SQL/62486/
                       WHERE t.N <= 8
                     ) mv
             )
        THEN 'Valid'
        ELSE 'Not Valid'
        END
go