Here's the generic setup: a spreadsheet with different products in the left column and quantity sold in the columns to the right with the month advancing with each column. So, the headers would look like this:

Product,JanuaryQuantity,FebruaryQuantity, etc.

Let's say that we have a sporting goods store for the example. I want to change the format so there are three columns: Product,Month,Quantity.

So, for example, there would now be rows like this:

Baseballs,January,10
Baseballs,February,15
Basketballs,January,10
etc.

How do I transform a spreadsheet like the one I initially mentioned into one like this? It seems to be beyond the functionality of Pivot Tables, but I may be wrong.