Strip Non Numerics in Query

create function[dbo].[fn_StripNonNumeric]( @string varchar(max))
returns varchar(max)
as
begin
if patindex('%[^0-9]%', @string) > 0
while patindex('%[^0-9]%', @string) > 0
set @string = stuff(@string, patindex('%[^0-9]%', @string), 1, '')
return @string
end