Book Image

Hands-On Business Intelligence with DAX

By : Ian Horne
Book Image

Hands-On Business Intelligence with DAX

By: Ian 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

Calculating cumulative totals

In the previous section of this chapter, we looked at creating a quick measure for year-to-date totals. The DAX expression that is created for this measure is an example of the Cumulative Total pattern. In this case, the pattern is used to create a running total of the Sales Amount field by the Date field.

The following code is the DAX expression that was created for this example:

Sales Amount running total in Date =
CALCULATE (
SUM ( 'Sales'[Sales Amount] ),
FILTER (
ALLSELECTED ( 'Date Table'[Date] ),
ISONORAFTER ( 'Date Table'[Date], MAX ( 'Date Table'[Date] ), DESC )
)
)
  • The expression works by using the FILTER and ISONORAFTER functions to return a table of dates that are less than or equal to the date of the current row.
  • The measure then calculates the SUM of Sales Amount for all sales...