Where DAX fits in, and where to find it

In an analytics solution based on the Microsoft platform, DAX is used in the Analyze layer. DAX lives inside analytical models as the formula language to define calculations and other logic. In fact, models and DAX are really two sides of the same coin: the design of the model impacts the complexity of the DAX code, and your skills in DAX determine your model designs (we will elaborate on the core concepts of data models in Chapter 1.2, Model Design).

The power of DAX is in its strong data aggregation capabilities. The DAX language contains many functions and constructs for defining a variety of aggregations to generate results that lead to the insights needed. In the past, many types of aggregations could not be created directly but had to be implemented through specifically preparing data. For instance, computing a year-to-date sales total can be done in DAX with a single function, while in Excel or traditional reporting tools, separate...