I expected function like that. Is string numeric or not.

CREATE FUNCTION [dbo].[IsAlphaNumeric](

@input varchar(100))

RETURNS bit

AS

BEGIN

DECLARE @i int, @max-2 int, @C varchar(1)

DECLARE @isAN bit

SET @max-2 = LEN(@input)

SET @isAN= 1

SET @i = 0

WHILE @i < @max-2 BEGIN

SET @i = @i + 1

SET @C = SUBSTRING(@input,@i,1)

IF PATINDEX('%[0-9]%', @C) = 0 BEGIN

SET @isAN = 0

BREAK

END

END

RETURN @isAN

END