I would use REGEXP function in Virtual DataPort to remove the characters or numbers from a string.
For example, you could remove characters from a field by using something like this:
REGEXP('streetname123','[a-zA-Z]','') as housenr,
REGEXP('streetname123','[0-9]','') as street
You could refer to the community question [Special character](https://community.denodo.com/answers/question/details?questionId=90670000000XczwAAC&title=Special+character) to know about using REGEXP function .
Hope this helps.