Josh O. wrote...
....
The vlookup and the vlookups (from alan) both are close to what I
need. The
vlookup fuction entered as an array will lookup the customer number in
each
row and return the data I need, except when a customer has 2 or more
open
invoices. The vlookups (from alan) function will list each invoice,
but will
only lookup one value (or customer). Manually entering that formula
for each
customer number is too time consuming. I know there is some way to do
this,
I just can't figure out the most efficient way to handle.

I kinda figured this was the case.

If the CSV file is basically tabular, possibly with blank cells but
with well-defined columns/fields, then there's no good reason to use
formulas to extract information. Sort on the customer number column
then on the invoice number column. Then delete any cruft sorted to the
top or bottom, then select the remaining data and use Data Subtotals
- even if you don't want subtotals. You can then use an autofilter to
filter blank cells in some column in the subtotal rows and then clear
those rows, thus creating blank rows between customers. If you don't
wan multiple instances of the customer number to appear beside each
invoice record, follow my previous instructions for how to remove
second and subsequent instances using filters.

If your data isn't basically tabular, then you need to provide a lot
more details about what it does look like. VLOOKUPS won't be of much
help to you in this case. Neither would VLOOKUP, for that matter.