=If(B15="","",VLOOKUP(B15,Products,2))
Its often safer to use the 4 argument Vlookup set to false, unless you can
be certain your source list will be sorted :

=If(B15="","",VLOOKUP(B15,Products,2,FALSE))

cheers
Simon

"Excel Student" wrote in message
...
In an invoice I am making I want to use the vlookup function to populate a
description column and a unit price column when I type in a product item
number. I have a product table set up with the item number, description
and
unit price on it. However, when I do not have an entry in the product
item
numberin the invoice, an error message appears in the description column
and
unit price column which does not make a good appearance for my invoice.

How to I put the =If(B15="","","") function in the vlookup function
=VLOOKUP(B15,Products,2)