What Is Dax in Power BI?

Data Analysis Expressions (DAX) is a popular formula language that enables custom calculations in Power BI.

Using DAX, you can extract new information from the data that is already present in your model.

Need help in creating your own business metrics and calculating growth indicators? DAX can help you with that as well.

In this blog, I will explain what DAX is in simple terms. I will also show you how to create your own DAX formula in Power BI.

___________________________________________________________________________

Whether it’s Google or Tesla, most successful businesses around the world are now entirely dependent on data for their daily functioning.

Understanding your data has become more critical than ever to stay one step ahead of your competition. 

But to make smarter choices using your data, you need to go beyond just raw numbers.

You need tools that can help you answer complex questions using your data.

That is where DAX in Power BI comes in! It enables you to obtain deep insights from your raw data.

Want to learn how? Read the guide below, which includes detailed tutorials on what DAX is and its various functions in Power BI.

By the end of this guide, you will learn how to unlock the full potential of DAX in Power BI.

Let’s dive in!

1. What is DAX?
2. Key Characteristics of DAX
3. Why is DAX so Important?
4. DAX Formulas vs. Excel Formulas
5. Core Concepts of DAX
6. Common and Useful DAX Functions
7. How to Start Using DAX: A Simple Power BI DAX Tutorial
8. Introduction to Power BI DAX Variables
9. When Do You Need Professional Data Visualization Services?
10. Final Verdict: Unleashing the Power of DAX
11. FAQs

DAX is the formula language of Power BI. It is what makes doing complex calculations in Power BI possible.

So what is it? In essence, DAX is a collection of operators, functions, and constants.

Think of DAX as a simple math problem you give to Power BI to get the result you need in your table.

Why Use DAX in Power BI? 

DAX is a versatile tool that can be used to:

• Obtain new information from the data you have collected 
• Perform multiple complex calculations and data comparisons 
• Build dynamic business logic that changes according to user inputs 

I use DAX daily to create powerful data visualizations from my Power BI reports. It has helped me move beyond doing simple sums and counts in my tables.

Want to learn how DAX can help you? Let’s start by exploring it’s key features:

Here are some of the best features that DAX can unlock for you in Power BI:

1. Versatile Applications: DAX is a great tool for anyone who needs more depth in their results. For example, DAX can calculate key metrics like profit margins, YOY growth and running totals directly from your data. 
   
   
2. Enhances Data Models: DAX can create an intelligent layer on top of your raw data. This means that DAX can automatically tag sales to “High” or “Low” priority, helping you see patterns that you may have missed.
   
   
3. Fully Interactable: DAX adapts to user inputs and provides many automated features. For example, you can click a filter to specify a time or region, and DAX will automatically update your entire dataset to match your filter.
   
   
4. Rich Function Library: The formula language boasts a massive library of ready-to-use functions. Functions like SUM and CALCULATE can be combined into a single DAX formula for more straightforward calculations.

The characteristics above show just how powerful DAX is for analyzing data in Power BI. It might take you some time to master it, but its payoff is truly worth it when you create a Power BI dashboard.

You are probably wondering, “Why can’t I just build charts without using DAX in Power BI?” Technically, you can. But your charts will never have the same depth and clarity as visualisations built with DAX formulas.

DAX can help you:

• Unlock custom calculations for business-specific metrics. 
• Enable complex comparisons for advanced analytics. 
• Improve data integrity through consistent business logic. 

Thus, using DAX in Power BI can significantly improve your data analysis.

In many ways, DAX in Power BI is similar to using formulas in Excel. However, there is a key difference between these two features:   

This is why a simple formula using DAX follows a format like: 

Total Sales = SUM(Sales[Revenue])

While an Excel formula for the same purpose would look like:

Total Sales = SUM(B2:B10)

To better understand what DAX is in Power BI, you need to understand these three concepts:

1. Syntax

This is the base structure of every DAX formula. Syntax shows the relationship between two or more variables in the formula.

Example: Profit margin = SUM ( financials[Profit] ) / SUM ( financials[Sales] )

2. Functions

These are the verbs in DAX that help describe the action to be performed:

• Aggregation: SUM, AVERAGE.
• Filtering: CALCULATE.
• Time Intelligence: TOTALYTD.
  
  

3. Context

Context specifies exactly what the user needs to include in the formula during the calculation. DAX works by understanding which data you are pointing to, so it can calculate the correct values taken from your table. 

The two main types of contexts are: 

1. Row context: This lets the DAX formula know which row to use. 
2. Filter context: This is applied on top of a row context to signify a subset of a row or column. 

Example: In the formula USA Profit Margin = CALCULATE ( SUM ( financials[Profit] ))

Here, CALCULATE is a filter context, and [Profit] is a row context signifying the exact row of the table. 

Let’s look at primary functions in DAX that you are likely to use regularly: 

• SUM: Used to add up numbers in a particular column. 

Example: Total Revenue = SUM(Sales[Revenue])

• CALCULATE: A powerful function that can change the context of the calculation. 

Example: US Revenue = CALCULATE(SUM(Sales[Revenue]), Sales[Country] = "USA")

Excited to start using DAX in Power BI?

Let’s make things easier by first understanding how you can measure values using DAX in Power BI.

For this, we will use an example scenario that demonstrates how to use DAX to calculate the total and average sales for a report. 

1. Open your Power BI report and go to report view. 
2. Create a New Measure by right-clicking on the table. 
3. Type the DAX: Total Sales = SUM(Sales[Revenue]). 
4. Press Enter. 
5. Use this Measure by dragging the Total Sales measure onto a new canvas.

Great work! You have now completed the first step towards learning how to use DAX in Power BI. Now let’s learn about other DAX variables you can use in Power BI. 

As formulas continue to grow, your workflow may get cluttered. Power BI DAX Variables can make them look cleaner.

For example: 

• Without a Variable: 

text

Total Profit YTD =

CALCULATE([Total Sales] - [Total Cost], DATESYTD('Date'[Date]))

• With Power BI DAX Variables (Cleaner): 

text

Total Profit YTD =

VAR TimePeriod = DATESYTD('Date'[Date])

VAR TotalProfit = [Total Sales] - [Total Cost]

RETURN

    CALCULATE(TotalProfit, TimePeriod)

Using DAX variables in Power BI can thus provide a more refined look to your tables. It can help you understand clearly what each line of the formula represents. 

This is just the beginning! Learning DAX in Power BI can be quite difficult for advanced use cases like Time Intelligence and Dynamic Segmentation.

This is where an expert can help make your learning journey easier.

Consider opting for professional data visualization services when:

• Your business logic seems very complex 
• Reports have become slower in response 
• You require a more scalable data model 
• Your team lacks the required expertise 

An experienced provider of data visualisation services can help you build the right solution.

They can also help train your team in using DAX for advanced reporting. 

In this blog, I have helped you understand the basics of DAX and the required beginner steps of this journey. But implementing this in real-world scenarios to solve Power BI issues can pose serious challenges.

Luckily, you can always reach out to our experienced team at Augmented Tech Labs!

We have helped many leading enterprises build their own DAX-based models using Power BI.

Connect with us today, and we will help you understand the next steps in how you can use DAX to streamline your next project!

1. What is the main use of DAX in Power BI?

The main use of DAX in Power BI is to create custom calculations and business metrics that are essential for advanced analysis.

2. Is DAX in Power BI similar to SQL?

They are quite different in practice. DAX in Power BI is for analyzing data within a model, while SQL is for database querying.

3. What is the best way to learn DAX in Power BI?

The best way is to start using DAX on your own. Begin with simple measures and follow a Power BI DAX tutorial to understand context.

4. Can I use DAX in Power BI without coding?

Yes, but only for the basics. Advanced DAX in Power BI requires logical thinking and practice, alongside an experienced software partner to help you along the way.

5. Why are my DAX in Power BI measures slow?

Slow measures in DAX in Power BI are often due to a poor data model. Using Power BI DAX variables and our recommended practices can help boost your measures significantly.