Wat about the following:
John D Smith
John Smith
Billy Bob Johnson
Juan San Pedro
Juan Marco San Pedro
You really can't do this easily. Fix your data structure and go back and
fix the records manually. You might try to do SOME of them using update
queries. You could run a query to find all records with only one space.
Then move them into first and last name. You could find all cases where the
middle name is only one character (initial) and sort them into the three
fields. Then, handle whats left manually.
You'll have to play around with the queries to identify the ones you can
using the logic I just mentioned. Or, you might want to just update them
all, then go back and look for exceptions by manually reading the list.
Good Luck.