Overview of DAX in Power BI
Overview of DAX in Power BI

Augment your Power BI data model with custom DAX measures to improve efficiency and provide better metrics for your users. Power BI comes with an extensive range of built-in functions that assist with many common report scenarios. But sometimes, you'll need to create your own measures where the "out of the box" ones don't do exactly what you want or exhibit unintended behavior.

In addition to scenario-specific functions, Power BI has general-purpose functions that you can use in DAX statements to create complex custom measures. This course explores the use of specific and general functions with DAX to address several scenarios.

Learning Objectives

  • Learn how to replace numeric columns with measures that use SUMX and CALCULATE functions
  • Learn about Time Intelligence functions and how to make year-on-year and month-on-month reports using time-based functions and custom DAX measures
  • Learn how to use Time Intelligence functions and custom DAX to create semi-additive point-in-time measures

Intended Audience

This course is intended for anyone who wants to learn how to use DAX to build measures in Power BI.


To get the most out of this course, you should have a basic understanding of Microsoft Power BI.


In this course, we look at creating DAX measures in three different scenarios. We start by using the functions SUMX and CALCULATE to create measures to replace numeric columns in our dataset. Calculate is one of the most useful and adaptable DAX functions in Power BI. Calculate evaluates an expression within the context of its own filters, or as Microsoft says, "Evaluates an expression in a modified filter context." Most DAX functions operate within a context, whether the universal context of the dataset, the context of a data row, or slicer. Calculate enables you to apply a context to the expression outside of the current context through extra filters.

In the following scenario, we create a typical sales report overtime where we compare year on year and month on month values. Then I'll demonstrate some of Power BI's Time intelligence functions and how to overcome undesired default behavior. The final scenario also involves Time intelligence functions but through the lens of semi-additive measures. I look at the default behavior of the closing balance function and how we can overcome its shortfalls by using the CALCULATE, LASTNONBLANK, and PARALLELPERIOD functions.

Let's jump into writing some DAX.

About the Author
Learning Paths

Hallam is a software architect with over 20 years experience across a wide range of industries. He began his software career as a  Delphi/Interbase disciple but changed his allegiance to Microsoft with its deep and broad ecosystem. While Hallam has designed and crafted custom software utilizing web, mobile and desktop technologies, good quality reliable data is the key to a successful solution. The challenge of quickly turning data into useful information for digestion by humans and machines has led Hallam to specialize in database design and process automation. Showing customers how leverage new technology to change and improve their business processes is one of the key drivers keeping Hallam coming back to the keyboard.