I'm sure this is easy, but I'm searching and can't find it.

Column A has a unique number (identifying a customer). Column B has a sales figure. I have 4 sheets in this document. 2008, 2009, 2010, and 2011. The unique numbers in column A are not the same from year to year. There are many that are common to all or some years, but each year has it's own different list.

For the sheet with 2008, I want to add a row C for 2009, to show the values for the next year (IF the customer was on the next year's list).

The logic is something like this: If A2 exists anywhere in column A of sheet 2 (the 2009 sheet), return the corresponding value of Row B from sheet 2.

Using the LOOKUP wizard gets me part of the way - but the result vector is where I'm stuck. How do I specify the source of the return value? If the unique ID number was found in A72 from the second sheet, I want it to return the value from B72.

I assume I can have it return something like "NA" if the customer is not on the next year's list.

I hope I'm explaining this coherently.

Much appreciated!