A table calculation is a way to take the results of usual calculations, as defined in the previous chapters, and perform additional calculations based on those results (and not on the underlying data).

Let's take an example of a table calculation that looks at the average of SUM(Profit) by Year (Order Date) (we will learn how to create such a calculation later in this chapter):

In this instance, the average is calculated by looking at the aggregated marks (in this case, ($248,941+$307,415+$406,935+$504,166)/4 = $366,864), not by averaging the profits in the underlying data.

There are two main components to a table calculation in Tableau. The first element is the calculation that we want to perform on those marks (in this case, a straight average on the marks). The second is the scope (or partition), which we will look at in the...