A Neat Trick in Excel: VLOOKUP

Lately I have been doing a lot of data analysis. One of the tools I have been using is Microsoft Excel and I recently learned a new trick using VLOOKUP. I thought I would put the information here in case I ever need it again. Oh and it may help you as well.

Most of the time I work with data, I use a relational database. That allows me to join various tables to replace cryptic values with more descriptive ones. A classic example is that of an EMPLOYEE table that uses a department number instead of the name. The database will then have a lookup table that converts the number into the name. This saves a certain amount of space and makes for much more efficient queries.

You can do the same thing in Excel using the VLOOKUP function. In my spreadsheet I have 2 tabs with the first being the employee information and the second being the department. Let's assume the employee tab has the following information:

	A	B	C
1	Firstname	Lastname	Deptno
2	Matthew	Bennett	10
3	Mike	Smith	20
4	Sara	King	30

 Now let's assume that those department numbers translate to something much more readable like:

	A	B
1	Deptno	Name
2	10	Research
3	20	Operations
4	30	Finance

You can use the VLOOKUP function in the 4th column of the table to include values from the department tab. It has the following syntax:

VLOOKUP(LookupCell, TabName!StartCell:EndCell, PasteColumn, Match)

So the LookupCell is that of the number that we want to convert to descriptive text. In the example above, we would use the column C values. 

The next values to fill in are that of the lookup table. While we could have them on the same page of the workbook, I find it easier to list them on a different one and call it the "department" tab. There are only 3 values and so we would start in column A on the second row. We would then run to B4.

The PasteColumn corresponds to the column number on the lookup tab that contains the value we want to show. Our descriptive text is in the 2nd column and so we would use the value "2".

The Match parameter indicates if we want to use an approximate or exact match. This example uses an exact match and so it should be set to "FALSE". I haven't tried doing an approximate match and so I am not sure of a use case for setting it to TRUE. Perhaps I can play with it for another blog entry.

Now let's put it all together. In cell D2, I would use the following value:

=VLOOKUP(C2, department!$A$2:$B$4, 2, FALSE)

I would then copy that formula and paste it into cells D3 and D4.

If those dollar signs confuse you, that is to hold the values constant regardless of what cell you paste the formula into. Otherwise Excel will adjust the reference. In the above example, the C2 reference doesn't have the dollar sign and will be converted into C3 when you paste it in the C3 cell.

This really helped me with some analysis I did and so I hope it helps you too.