Category: Microsoft Fabric

Business Intelligence - BI, Data Visualisation, DAX, Microsoft Fabric, Power BI, Power BI Desktop, Power BI Desktop RS

Understanding Power BI Totals: The Math, the Model, and the Misconceptions

The long-running debate around how Power BI calculates totals in tables and matrices has been part of the community conversation for years. Greg Deckler has kept the topic alive through his ongoing “broken totals” posts on social media, often suggesting that Power BI should include a simple toggle to make totals behave more like Excel. His continued campaign prompted a detailed reply from Daniel Otykier in his article “No More Measure Totals Shenanigans“, and earlier, Diego Scalioni explored how DAX evaluates totals internally in his post “Cache me if you can: DAX Totals behind the scenes“.

This blog brings all those perspectives together from a scientific and comparative angle. It looks at how totals are calculated in Power BI and compares that behaviour with Tableau, Excel, Paginated Reports, and even T-SQL. The goal is not to take sides, but to clear up the confusion around what is happening under the hood.

Are Power BI Totals Really Broken?

Let’s get one thing clear right at the start, no, Power BI totals are not broken. There is no “it depends” this time. What some interpret as broken behaviour is actually how DAX and the underlying model are designed to work.

This post is not personal, it is purely scientific and technical. While I have great respect for Greg and his significant contributions to the Power BI community, I disagree with the use of the word “BROKEN.” It sounds dramatic but does not reflect the full truth. Totals in Power BI behave exactly as the model and the maths define them to. Want to know why? Keep reading.

Why this matters

When someone with Greg’s influence keeps saying totals are “broken”, it really affects how new users see Power BI. Some even start thinking the tool itself is not reliable, when what they are seeing is actually how different reporting tools do their calculations in different ways.

It helps to know the main calculation styles that these tools use:

  • Cell based: This is what you get in worksheet formulas and classic PivotTables that use Excel ranges. Totals are just simple sums of the shown items, with no model or relationships behind the scene.
  • Model driven: This is how Power BI works and also Excel PivotTables that use the Data Model (Power Pivot) or connect to a tabular dataset. Measures are calculated again for every context, so totals depend on how filters and relationships are set.
  • Query driven: Tools like Paginated Reports work this way. The report runs a query, for example SQL or DAX, gets the dataset, and then sums or averages values in the report design. The author decides how each total should be calculated.
  • Hybrid (query and context driven): Tableau fits in here. It gets the data through a query but also lets you change the level of detail and how totals behave in the visual. So sometimes it acts like a query tool and sometimes more like a model one.

Most of the confusion happens when people compare results from these tools as if they all worked the same way. Once you understand the difference between cell based, model driven, query driven, and hybrid tools, the way Power BI shows its totals starts to make full sense.

The problem that started it

Greg’s long-running example uses a small table with a single column of numbers and a DAX measure like this:

SUMX(SampleData, SampleData[Amount]) - 10

In the total row, the result shows 590, while he expects 580 (two groups of 290 each). Based on that, he argues that Power BI totals are “wrong”.

But DAX is only doing what it is told to do. In this measure, the subtraction of 10 happens after the total amount is calculated, not for each row. If the intention was to take 10 away per row, then the measure should be written like this:

SUMX(SampleData, SampleData[Amount] - 10)

This version gives the expected 580 because the subtraction now happens at the lowest level of detail, which is per row.

This might look like a small detail, but it is exactly where most of the confusion around totals begins. The difference is not about Power BI being wrong; it is about understanding where in the calculation the operation happens.

The math behind it

Before we look at the numbers, let’s first talk about what we are trying to do. We Greg’s small and very simple table that shows some amounts by Category and Colour:

CategoryColourAmount
ARed100
AGreen100
ABlue100
BRed100
BGreen100
BBlue100
Continue reading “Understanding Power BI Totals: The Math, the Model, and the Misconceptions” →
Azure, Azure SQL Database, Business Intelligence - BI, Fabric Administrator, Fabric Capacity, Microsoft Fabric, Power BI, Power BI Governance, Power BI Service, Purview

Sharing Power BI Reports with External Users – Part 3: Sensitivity Labels, Encryption, and Secure Sharing

Sharing Power BI Reports with External Users the Right Way, Part 3: Sensitivity Labels, Encryption, and Secure Sharing

In Part two of this series, we walked through how to configure your Microsoft Fabric environment to securely share Power BI reports with external users across Microsoft 365 tenants. We covered licensing requirements, admin portal settings, how to invite guest users, and how to share reports directly with them.

Now, in the third and final part of this blog series, we focus on two important areas that are often overlooked:

  • What happens when Microsoft Purview sensitivity labels are applied to a report
  • How to refine admin portal settings to better control guest users’ access to Fabric

This series was originally created to support a YouTube video I published in April 2025. The topic turned out to be too broad to explain well in one blog, so I decided to split it into three parts.

Here is the complete series:

  • Part 1: Understanding the Problem and Core Concepts
    This post explains why external sharing can be tricky, the key requirements to get it working, important terminology, user roles, and how the whole process fits together.
  • Part 2: Hands-On Guide to Setup and Sharing
    A step-by-step walkthrough of how to share reports across tenants, covering licensing, admin portal settings, inviting guest users, and how report access looks from the guest’s side.
  • Part 3: Sensitivity Labels, Encryption, and Secure Sharing (this blog)

In this last part, we will look at what happens when Microsoft Purview sensitivity labels are applied, including access control, and will also discuss key admin settings you may need to adjust for more secure collaboration.

If you like to listen to the content on the go, here is the AI generated podcast explaining everything about this blog 👇.

If you are someone who prefers video over reading, you can watch the full walkthrough here 👇.

Let’s now get into the final piece of this guide.

Sensitivity Labels in Microsoft Fabric

Microsoft Purview sensitivity labels are part of a broader Purview Information Protection framework. These labels are not exclusive to Microsoft Fabric or Power BI. They are designed to be consistently applied across various Microsoft services, including but not limited to Outlook, Word, Excel, SharePoint, and Azure SQL DB. This ensures that data is classified and protected uniformly, regardless of where it is created, stored, or shared. In the context of Power BI, when you apply a sensitivity label to a report, it adds classification metadata and, if configured, applies protection such as encryption and access restrictions. These protections travel with the content. For example, if a report is exported to PDF or PowerPoint, and the label has encryption enabled, that exported file will also be encrypted. So only the users who are authorised to view the content will be able to open it, even outside of the Power BI service. This means your data remains secure not only inside your tenant but also when it moves across users, devices, and even organisations.

What Happens When You Share Encrypted Reports?

Let’s walk through an example.

You share a Power BI report with a guest user. This report has a label applied that encrypts its content. Here is what the guest user can and cannot do:

Continue reading “Sharing Power BI Reports with External Users – Part 3: Sensitivity Labels, Encryption, and Secure Sharing” →
Azure, Fabric Administrator, Microsoft Fabric, Power BI, Power BI Governance

Sharing Power BI Reports with External Users – Part 2: Hands-On Guide to Setup and Sharing

In Part one of this series, we covered the foundational concepts behind sharing Power BI reports with external users. We explained why this is more complex than it seems, outlined the key requirements, clarified essential terms like guest users and Entra ID, and defined the roles involved in setting up secure external access.

Now that we have the groundwork in place, it’s time to walk through the process step by step.

This blog is based on the walkthrough portion of my YouTube video published in April 2025, where I explained the scenario and how to implement it, from configuring the necessary settings to sharing reports across two Azure tenants.

Here’s a quick guide to the full series:

  • Part 1: Understanding the Problem and Core Concepts
    This post explains why external sharing can be tricky, the key requirements to get it working, important terminology, user roles, and how the whole process fits together.
  • Part 2: Hands-On Guide to Setup and Sharing (this blog)
    A step-by-step walkthrough of how to share reports across tenants, covering licensing, admin portal settings, inviting guest users, and how report access looks from the guest’s side.
  • Part 3: Sensitivity Labels, Encryption, and Secure Sharing
    An in-depth look at what happens when Microsoft Purview sensitivity labels are applied, including access control, encryption, and key admin settings you may need to adjust for secure collaboration.

In this post, we’ll focus on a practical scenario. One organisation, let’s call it Tenant A, wants to share a Power BI report with someone from another organisation, Tenant B. We’ll cover everything from verifying licenses to configuring the Fabric Admin Portal and inviting the external user. If you’re looking to follow along, this guide will give you a clear path to replicate the same setup in your environment.

If you like to listen to the content on the go, here is the AI generated podcast explaining everything about this blog 👇.

If you are someone who prefers video over reading, you can watch the full walkthrough here 👇.

Scenario Overview

Let’s imagine we have two different Azure tenants. One belongs to the organisation that owns the Power BI report (Tenant A) and the other belongs to a partner or customer who needs access to that report (Tenant B).

The objective is to share a report from Tenant A with a user in Tenant B, in a secure and controlled way.

We will go through the steps the admin and report owner in Tenant A need to follow to make this work properly.

Step 1: Verify Power BI Licensing

Before setting up anything, make sure both users involved have a valid Power BI license. This might seem obvious, but it is a very common reason why external sharing fails or behaves unexpectedly.

In the demo example:

  • The report owner in Tenant A has a Power BI Pro license.
  • The external user from Tenant B (named Nestor) also has a Power BI Pro license.

You can confirm this by clicking the Account Picker icon in Microsoft Fabric and looking at the License type. If the external user does not already have a Pro or PPU license, you either need to assign one through your tenant or ask them to obtain the license.

Continue reading “Sharing Power BI Reports with External Users – Part 2: Hands-On Guide to Setup and Sharing” →
Azure, Fabric Administrator, Fabric Capacity, Microsoft Fabric, Power BI

Sharing Power BI Reports with External Users – Part 1: Understanding the Problem and Core Concepts

Sharing Power BI reports with external users is a common but often misunderstood scenario. While it may seem simple on the surface, doing it properly and securely involves many moving parts. I’ve already published a video on this topic, which turned out longer than expected because of the number of details involved.

To make this blog easier to follow and more digestible, I’ve broken the content into a three-part blog series. Each part covers a focused area of the topic:

Part 1 (this blog): Understanding the Problem and Core Concepts This post explains why external sharing can be tricky, the key requirements to get it working, important terminology, user roles, and how the whole process fits together.

Part 2: Hands-On Guide to Setup and Sharing A step-by-step walkthrough of how to share reports across tenants, covering licensing, admin portal settings, inviting guest users, and how report access looks from the guest’s side.

Part 3: Sensitivity Labels, Encryption, and Secure Sharing An in-depth look at what happens when Microsoft Purview sensitivity labels are applied, including access control, encryption, and key admin settings you may need to adjust for secure collaboration.

If you like to listen to the content on the go, here is the AI generated podcast explaining everything about this blog 👇.

If you are someone who prefers video over reading, you can watch the full walkthrough here 👇.

Introduction

Are you a Power BI developer or someone in a BI or finance team who needs to share reports with customers, partners, or vendors? If they are not part of your Microsoft 365 tenant, things get a bit more complex than just clicking the “Share” button.

This is a common need, especially in consulting scenarios, but doing it securely and correctly takes more than people often think. It involves both technical setup and a clear understanding of roles and terminology.

Continue reading “Sharing Power BI Reports with External Users – Part 1: Understanding the Problem and Core Concepts” →