Tabular Basket Analysis: Simple Data Mining in Tabular databases

I was recently reading Alberto's amazingly awesome piece on basket analysis in tabular in DAX (available here), but I had some issues implementing it on my own. I wanted to blog about this in case anyone else ran into the same issues I did when trying to implement it. At its core what the question is really asking is "Of everyone that bought Product X, who didn't buy Product Y"? This can be a very tricky question to answer from a business intelligence perspective, but the value it gives to the business is amazingly useful. Firstly, some background. To keep this simple I am going to be using the same data set Alberto did, on Internet Sales in Adventure Works. The specific question we want to answer is: "Of everyone that purchased a mountain bike, who didn't buy a tire accessory?" My tabular model that I use for all of my dax stuff is pretty big, but the sub-model snippet we want to initially look at looks like: