Analysis of items ordered together

[sbrien]

I am trying to analyze our company's sales data to better understand which items frequently sell together so that we can better organize our inventory and cut down on time to assemble orders.

The data is organized by order number and product number.

My initial thought was to take the top 1000 or so items and set them up along the x and y axes. I would run some kind of count formula that would identify the distinct number of order numbers that included the items from both the x axis and y axis. Does anyone know how I could set up that count formula?

Order Number	Product Number
111	123
111	456
111	789
222	456
222	789
333	123
333	789

<tbody>
</tbody>

	123	456	789
123	x	1	2
456	1	x	2
789	2	2	x

<tbody>
</tbody>

Any thoughts on how to accomplish this kind of analysis?
Thanks!