Vlookup is a somewhat tricky command to understand initially, but can be used as a "powerful" tool (powerful is subjective, hence the quotes) that is similar to a database join, if you are familiar with that.
Anyway, here is an example, assuming you have Sheet 1 and Sheet 2 with data in Sheet 1, Column A that matches the Data in Sheet 2, Column A by data type. Let's further say that they are of format 'last name, first name'. Also, data begins in cell A2, since A1 is a title row. Sheet 1 and Sheet 2 can either be in the same workbook, or in separate workbooks.
in Sheet 1, cell B2, you can begin your vlookup by typeing in:
=vlookup(
Then click on cell A2. This tells Excel that you are looking for a value that matches A2.
That should now make the formula look like
=vlookup(A2
Now press the comma key - this tells excel that you are ready to tell it where to look for the matching contents. At this point, you need to click on Sheet2 and highlight column A by clicking on the A at the top of that column (in the gray area).
If you are doing 2 sheets in the same workbook, the formula will now look like: =vlookup(A2,Sheet2!A:A
press the comma key. This indicates that you are ready to tell Excel what value you want to return. The value you are about to enter is a column in a position relative to the column you just selected. In our case, we only highlighted one column, b/c we were only interested in that column's values. If you wanted to return the value of the cell in column B instead, you would have highlighted column A and B. In other words, you can look for a value in Column A, and return a value from column B (or any other column) as long as you highlight all of the columns. We are going to tell it column 1 (again, because we only highlighted one column, and we are just testing for existence of the value)
Anyway, our formula should now look like this:
=vlookup(A2,Sheet2!A:A,1
Press the comma key again. We are now ready to tell Excel to look for an exact match. Do this by typing in 'false' after the comma (minus the quostes) and close the formula with a right parentheses.
The final formula should look like this:
=VLOOKUP(A2,Sheet2!A:A,1,FALSE)
Copy this down in sheet 1 for as many cells as there are values in column A in Sheet 1. The result will display either the same value, or a #N/A. The #N/A's indicate that no matching value existed in Sheet 2. The cells with the same value indicate that the value exists in both sheets.
If you take all of the #N/A rows from sheet 1, and combine that with all of the rows in sheet 2, you will have a population of all rows with no duplicates (assuming there were no duplicates in Sheet 2 to begin with).
Hope this helps.
colby