>In principal we could do that. Unfortunately the street number field is a text field. I tried to cast it to a number and in some cases there is still text in the street number field and it won't cast without an error.
>If you know away around that problem as well I'dd appreciate it.

I'm assuming sql server for backend here. You should be able to test the field value with ISNUMERIC and use a case to determine whether to cast the value or not.

SELECT
CASE isnumeric(var_name)
WHEN 1 THEN cast(var_name AS int)
ELSE 0
END AS numaddress
FROM MyTable