Right-click FROMADDRESS, as you want to populate that one, and open the Field Calculator.
- Check the Python button
- Check Show Codeblock
Now, in the bigger area you will insert this function:
def findSmallest(l_add, r_add):
if l_add < r_add:
And in the smaller part below the "pre-logic script code" you will call that function, like this:
This will iterate through each row in the table and put the value of R_ADD_FROM into l_add and the value of R_ADD_FROM into r_add, and then it will compare both. If l_add is smaller, it will write that one into FROMADDRESS (i.e. it will return it), and if it is not (i.e. if it is bigger), it will return the other value.
There is not right or wrong. You could surely do this with VB Script, but getting into Python is a smarter move as it is (becoming) the lingua franca of GIS scripting.