It is time for our annual review of what happened in the DAX and SQLBI worlds, and what we should expect in 2026!

New DAX features in 2025

This was a big year for DAX, with the public preview that started in September for two new features: user-defined functions (UDFs) and calendar-based time intelligence.

The user-defined functions are the most significant update to the DAX language since 2015, when Microsoft introduced variables. Can you believe that for more than five years we had to write DAX code without variables? Well, the user-defined functions we just mentioned will have an even bigger impact in the long term.

In five years from now, when you open a semantic model and find measures longer than 20 lines without functions invoked, you will immediately think that such code has to be “old”, or that it’s “weird”. The same feeling you may have today when you see no variables being used in a 40-line-long measure. More importantly, while you do need to understand variables to declare and use them, you do not need to understand all the details about functions to “consume” them. Therefore, I expect a proliferation of libraries of any kind. In large companies, complex algorithms and calculations will be written by a small number of expert developers and used by a large number of data analysts who may not have the same advanced DAX skills.

Calendar-based time intelligence is a fantastic feature we should have received many years ago. It’s wonderful; it works well, even though it requires a little patience and an initial investment in time and effort. For a new model with non-trivial calendar requirements, it is the way to go. But if you have existing models and reports… You should not rush to migrate. There are performance advantages in specific scenarios, but overall, many people may not find the additional investment (in learning and refactoring of existing models and reports) worth the benefits. Expect more tooling coming to help you benefit from this feature, but more about this later.

New DAX functions in 2025

The 21 new functions introduced in 2025 do not introduce new concepts; most are logical consequences of other features released this year. For example, the new Calendar-based time intelligence updated the parameters of all time intelligence functions (which now accept a Calendar argument) and included new functions that work with weeks and require a Calendar argument: CLOSINGBALANCEWEEK, DATESWTD, ENDOFWEEK, NEXTWEEK, OPENINGBALANCEWEEK, PREVIOUSWEEK, STARTOFWEEK, TOTALWTD.

We have several new information functions to investigate the type of an expression, which are helpful in DAX user-defined functions (UDFs) that receive an argument without type enforcement. Because of the new names and aliases for the data types, we have multiple functions for the same type (e.g., INTEGER and INT64; they are really the same). These are ISCURRENCY, ISINTEGER, ISBOOLEAN, ISDATETIME, ISDECIMAL, ISDOUBLE, ISINT64, ISNUMERIC, ISSTRING. In the same group, we also have the new INFO.CSDLMETADATA and INFO.DEPENDENCIES functions.

The only function added to the visual calculations is LOOKUPWITHTOTALS. Finally, EXTERNALMEASURE has been documented officially this year, but it had been in use since 2020, as it is used for composite models.

What SQLBI delivered in 2025

People are coming back to in-person events. This is a fact. While we don’t have as many local community events as we did before the pandemic, the trend is that they are growing. However, the consumption of technical content is moving in different directions. As we announced last year, we limited our in-person delivery time during 2025 because we had to produce new content:

We completed the third edition of the book, The Definitive Guide to DAX. It is an entirely new book; we barely reused any parts from the previous edition. Why? Years of experience teaching DAX have given us more ideas for explaining core concepts to both newbies and experienced DAX practitioners. The book also includes many new chapters and covers the latest DAX features, including Calendar-based time intelligence and User-defined functions.
We have already started delivering the updated content of the Mastering DAX classroom course, which will have a new form for all deliveries in 2026.
We published new content inside SQLBI+, our subscription service for advanced content for developers who create semantic models for Power BI, Analysis Services, and Fabric. In 2025, we released two courses inside SQLBI+: Security in Tabular Semantic Models and AI Workflows and agentic development for Power BI. Both courses offer a whitepaper along with hours of videos. We also released a new whitepaper, Understanding SUMMARIZECOLUMNS, which includes valuable, hard-to-find-elsewhere information that is vital if you plan to query a semantic model from outside Power BI or want to understand the inner workings of this powerful function.
We published more than 30 new articles and blog posts at sqlbi.com. These represent high-quality, free learning content on SQLBI, which we produce to support the community and help students who cannot afford the paid content.
We released DAX Lib, first repository for libraries of DAX user-defined functions. It is free, open-source, and driven by community contributions. We are so happy about the enthusiastic adoption of the tool! There are already more than 30 ready-to-use libraries on DAX Lib, and we are talking about a feature released only 3 months ago and that is still in preview. This is definitely something that will grow a lot over the next year.
Our partner company, Tabular Tools, released DAX Optimizer Basic for general availability. This is a new version of the full DAX Optimizer service. Everyone can evaluate their DAX code in a semantic model: no email, no login, no password, no installation.
In 2025, the SQLBI YouTube channel surpassed 125,000 subscribers. We continued to publish a video for each corresponding article every other week, plus a few other videos with interviews and other content. That’s another source of free learning for students that may not be ready to invest in a video course just yet.
The SQLBI Newsletter is now being sent out to 275,000 subscribers! This year we also celebrated 300 newsletters with a special number dedicated to AI in BI and a new comics that is still alive after several months. Will it survive until next year? We hope so!
Our sister company, OKVIZ, released Synoptic Panel v2 which turned out to be a huge hit. Ther are already 13 use cases showing very different solutions based on this visual: take a look at them, they are inspiring regardless of the use of custom visuals!

What’s coming in 2026

New Mastering DAX video course: We are currently recording the new Mastering DAX video course that will be available by the end of March 2026. Everyone with an active license for the current Mastering DAX video course on the day the new content is r...

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