Hi: I have a worksheet with these columns:

D = first name
E= last name
F = sandwich order
G= date
There are many duplicate D and E entries: that person may have come in many
times, and ordered many different sandwiches.

I've pasted my entire customer list into A, B, and C:
A= customer number
B= first name
C=last name

There are both duplicates and non-matches: many customers haven't been in,
or ever ordered a sandwich.

How do I attach the correct customer number to the D/E record? In other
words, i need it to read through columns, A, B, and C, match the names to D
and E, and then enter the customer number from A into some new column, H, so
I can delete A, B, and C, and have my info with correct customer numbers.  If
they were the same line, I'd certainly know how to carry over if names were
equal, but the fact that the match may be on any line confuses me.

Seems like this should be easy. Help?
Thanks.