Book Image

Extreme DAX

By : Michiel Rozema, Henk Vlootman
Book Image

Extreme DAX

By: Michiel Rozema, Henk Vlootman

Overview of this book

This book helps business analysts generate powerful and sophisticated analyses from their data using DAX and get the most out of Microsoft Business Intelligence tools. Extreme DAX will first teach you the principles of business intelligence, good model design, and how DAX fits into it all. Then, you’ll launch into detailed examples of DAX in real-world business scenarios such as inventory calculations, forecasting, intercompany business, and data security. At each step, senior DAX experts will walk you through the subtleties involved in working with Power BI models and common mistakes to look out for as you build advanced data aggregations. You’ll deepen your understanding of DAX functions, filters, and measures, and how and when they can be used to derive effective insights. You’ll also be provided with PBIX files for each chapter, so that you can follow along and explore in your own time.
Table of Contents (17 chapters)
Free Chapter
1
Part I: Introduction
6
Part II: Business cases
15
Other Books You May Enjoy
16
Index

Introduction to DAX context

The generic term for DAX context is evaluation context: it is the context in which a DAX formula is evaluated, leading to a specific result. We like to distinguish between three types of context:

  • Row context
  • Query context
  • Filter context

In most Power BI documentation and publications, only two types of context are identified: row and filter context. The term query context has been used in relation to Power Pivot in Excel since way before Power BI came into being (yes, we're that old), and we have kept using it. In our experience from DAX courses, distinguishing between query context and filter context helps people to understand more complex scenarios.

Let's look at each context type in more detail.

Row context

Row context is the type of context you work with when creating calculated columns. A DAX formula defining a calculated column is evaluated for each row in the table. The result of the calculation...