Book Image

Hands-On Business Intelligence with DAX

By : Horne
Book Image

Hands-On Business Intelligence with DAX

By: Horne

Overview of this book

Data Analysis Expressions (DAX) is known for its ability to increase efficiency by extracting new information from data that is already present in your model. With this book, you’ll learn to use DAX’s functionality and flexibility in the BI and data analytics domains. You’ll start by learning the basics of DAX, along with understanding the importance of good data models, and how to write efficient DAX formulas by using variables and formatting styles. You’ll then explore how DAX queries work with the help of examples. The book will guide you through optimizing the BI workflow by writing powerful DAX queries. Next, you’ll learn to manipulate and load data of varying complexity within Microsoft products such as Power BI, SQL Server, and Excel Power Pivot. You’ll then discover how to build and extend your data models to gain additional insights, before covering progressive DAX syntax and functions to understand complex relationships in DAX. Later, you’ll focus on important DAX functions, specifically those related to tables, date and time, filtering, and statistics. Finally, you’ll delve into advanced topics such as how the formula and storage engines work to optimize queries. By the end of this book, you’ll have gained hands-on experience in employing DAX to enhance your data models by extracting new information and gaining deeper insights.
Table of Contents (18 chapters)
1
Section 1: Introduction to DAX for the BI Pro
7
Section 2: Understanding DAX Functions and Syntax
14
Section 3: Taking DAX to the Next Level

Deep diving into row context

The simplest way to explain row context is by adding a calculated column to a table. Whenever we create a calculated column, the DAX expression behind it will be evaluated using the row context. Each row in a table will have its own row context that consists of the values in each of the columns for that row.

Let's show this by adding a calculated column to the Sales table. In this instance, we'll add a column that calculates the Sales Amount, plus an additional 20 percent to represent sales tax. We can do this using the following DAX expression:

Sales Amount with Tax = Sales[Sales Amount] * 1.2

Once created, DAX will iterate through all the rows in the Sales table, evaluating the expression using the value of the Sales Amount column of the current row. It will work its way through the table row by row, with each row providing the row context...