New Field From a Current Field Up to a Certain Character (In a Search)

I have a field named FieldA. It looks like this:

10.10.10.10->10.11.11.11

I want to create a new field (FieldB) that is everything left of the "->". I tried using LTRIM, among others, but I can't get it working. This "seems" easy. :)

Help?

Thank you!