Use VLOOKUP.
=VLOOKUP(CodeToLookup,sheet1!YourDatabase,2,0)
Copy down as necessary.

Example
The database here is A1:B10 on Sheet1. The answers to be returned in Column
B on Sheet2, based on the Codes kept in Sheet2 Column A.
On Sheet2 in cell B1:

=VLOOKUP(A1,Sheet1!$A$1:$B$10,2,0)
Copy down as necessary.

tj

"Tray" wrote:

I have 2 spreadsheets. One is a database of all our dealer codes and the
state they are located in. The other is a list of all dealer codes that took
part in a promotion. I would like to add a column to the 2nd spreadsheet and
have excel look up each dealer code and insert which state they are in.