Marco Russo
@marcorus.bsky.social
Consultant, speaker, book writer, mentor. Business Intelligence with Power BI, Analysis Services, and Power Pivot. Other info on sqlbi.com
*2025 DAX recap*
UDFs
Calendar-based time intelligence
21 new DAX functions
*SQLBI*
Definitive Guide to DAX 3rd ed.
SQLBI+ content
DAX Lib
DAX Optimizer Basic
Blog: https://www.sqlbi.com/blog/marco/2025/12/29/what-happened-in-the-dax-world-in-2025/
Video:
UDFs
Calendar-based time intelligence
21 new DAX functions
*SQLBI*
Definitive Guide to DAX 3rd ed.
SQLBI+ content
DAX Lib
DAX Optimizer Basic
Blog: https://www.sqlbi.com/blog/marco/2025/12/29/what-happened-in-the-dax-world-in-2025/
Video:
What happened in DAX in 2025
A recap of the news in the DAX and SQLBI world in 2025 and a preview of what is coming in 2026.Happy New Year!All links in blog post: https://www.sqlbi.com/b...
youtu.be
December 30, 2025 at 11:05 AM
*2025 DAX recap*
UDFs
Calendar-based time intelligence
21 new DAX functions
*SQLBI*
Definitive Guide to DAX 3rd ed.
SQLBI+ content
DAX Lib
DAX Optimizer Basic
Blog: https://www.sqlbi.com/blog/marco/2025/12/29/what-happened-in-the-dax-world-in-2025/
Video:
UDFs
Calendar-based time intelligence
21 new DAX functions
*SQLBI*
Definitive Guide to DAX 3rd ed.
SQLBI+ content
DAX Lib
DAX Optimizer Basic
Blog: https://www.sqlbi.com/blog/marco/2025/12/29/what-happened-in-the-dax-world-in-2025/
Video:
𝗕𝗼𝗼𝗸 𝘂𝗽𝗱𝗮𝘁𝗲: The third edition of *The Definitive Guide to DAX* is available in all formats.
The 𝗞𝗶𝗻𝗱𝗹𝗲 version experienced 𝗾𝘂𝗮𝗹𝗶𝘁𝘆 𝗶𝘀𝘀𝘂𝗲𝘀. If you bought it, you have 7 days to request a refund.
Read more in the FAQ: https://www.sqlbi.com/books/the-definitive-guide-to-dax-third-edition/
The 𝗞𝗶𝗻𝗱𝗹𝗲 version experienced 𝗾𝘂𝗮𝗹𝗶𝘁𝘆 𝗶𝘀𝘀𝘂𝗲𝘀. If you bought it, you have 7 days to request a refund.
Read more in the FAQ: https://www.sqlbi.com/books/the-definitive-guide-to-dax-third-edition/
December 20, 2025 at 11:17 AM
𝗕𝗼𝗼𝗸 𝘂𝗽𝗱𝗮𝘁𝗲: The third edition of *The Definitive Guide to DAX* is available in all formats.
The 𝗞𝗶𝗻𝗱𝗹𝗲 version experienced 𝗾𝘂𝗮𝗹𝗶𝘁𝘆 𝗶𝘀𝘀𝘂𝗲𝘀. If you bought it, you have 7 days to request a refund.
Read more in the FAQ: https://www.sqlbi.com/books/the-definitive-guide-to-dax-third-edition/
The 𝗞𝗶𝗻𝗱𝗹𝗲 version experienced 𝗾𝘂𝗮𝗹𝗶𝘁𝘆 𝗶𝘀𝘀𝘂𝗲𝘀. If you bought it, you have 7 days to request a refund.
Read more in the FAQ: https://www.sqlbi.com/books/the-definitive-guide-to-dax-third-edition/
This article+video describes the data model and DAX measures to analyze campaign effectiveness 𝗮𝗻𝗮𝗹𝘆𝘇𝗲 𝗰𝗮𝗺𝗽𝗮𝗶𝗴𝗻 𝗲𝗳𝗳𝗲𝗰𝘁𝗶𝘃𝗲𝗻𝗲𝘀𝘀 by separating 𝗮𝘁𝘁𝗿𝗶𝗯𝘂𝘁𝗲𝗱 𝘀𝗮𝗹𝗲𝘀 from 𝗶𝗻𝗳𝗹𝘂𝗲𝗻𝗰𝗲𝗱 𝘀𝗮𝗹𝗲𝘀.
#dax #powerbi
https://www.sqlbi.com/articles/measuring-the-impact-of-promotions-on-sales-in-power-bi/
#dax #powerbi
https://www.sqlbi.com/articles/measuring-the-impact-of-promotions-on-sales-in-power-bi/
December 16, 2025 at 11:02 AM
This article+video describes the data model and DAX measures to analyze campaign effectiveness 𝗮𝗻𝗮𝗹𝘆𝘇𝗲 𝗰𝗮𝗺𝗽𝗮𝗶𝗴𝗻 𝗲𝗳𝗳𝗲𝗰𝘁𝗶𝘃𝗲𝗻𝗲𝘀𝘀 by separating 𝗮𝘁𝘁𝗿𝗶𝗯𝘂𝘁𝗲𝗱 𝘀𝗮𝗹𝗲𝘀 from 𝗶𝗻𝗳𝗹𝘂𝗲𝗻𝗰𝗲𝗱 𝘀𝗮𝗹𝗲𝘀.
#dax #powerbi
https://www.sqlbi.com/articles/measuring-the-impact-of-promotions-on-sales-in-power-bi/
#dax #powerbi
https://www.sqlbi.com/articles/measuring-the-impact-of-promotions-on-sales-in-power-bi/
𝗗𝗔𝗫 𝗟𝗶𝗯 is quickly becoming the shared home for UDFs in DAX: 𝘁𝗵𝗲 𝗰𝗼𝗺𝗺𝘂𝗻𝗶𝘁𝘆 𝗵𝗮𝘀 𝗮𝗹𝗿𝗲𝗮𝗱𝘆 𝗰𝗼𝗻𝘁𝗿𝗶𝗯𝘂𝘁𝗲𝗱 𝟯𝟬+ 𝗹𝗶𝗯𝗿𝗮𝗿𝗶𝗲𝘀 that you can import into your Power BI models using TMDL scripts.
Watch what DAX Lib is, why it matters, and how you can start using it.
Watch what DAX Lib is, why it matters, and how you can start using it.
Introducing DAX Lib
DAX Lib is an open-source repository of User-Defined Functions (UDFs) for Power BI, Fabric, and Analysis Services. Learn how simple it is to import a library...
youtu.be
December 12, 2025 at 10:04 AM
𝗗𝗔𝗫 𝗟𝗶𝗯 is quickly becoming the shared home for UDFs in DAX: 𝘁𝗵𝗲 𝗰𝗼𝗺𝗺𝘂𝗻𝗶𝘁𝘆 𝗵𝗮𝘀 𝗮𝗹𝗿𝗲𝗮𝗱𝘆 𝗰𝗼𝗻𝘁𝗿𝗶𝗯𝘂𝘁𝗲𝗱 𝟯𝟬+ 𝗹𝗶𝗯𝗿𝗮𝗿𝗶𝗲𝘀 that you can import into your Power BI models using TMDL scripts.
Watch what DAX Lib is, why it matters, and how you can start using it.
Watch what DAX Lib is, why it matters, and how you can start using it.
The 3rd edition of The Definitive Guide to DAX is available.
We have seen quality issues with the Kindle format. You might want to wait for that.
PDF is the best format for rendering, with no quality issues.
Enjoy DAX!
We have seen quality issues with the Kindle format. You might want to wait for that.
PDF is the best format for rendering, with no quality issues.
Enjoy DAX!
The Definitive Guide to DAX, Third Edition - SQLBI
The Definitive Guide to DAX is an authoritative resource for mastering the DAX language, which is pivotal for creating measures for semantic models in Micro
www.sqlbi.com
December 8, 2025 at 9:39 PM
The 3rd edition of The Definitive Guide to DAX is available.
We have seen quality issues with the Kindle format. You might want to wait for that.
PDF is the best format for rendering, with no quality issues.
Enjoy DAX!
We have seen quality issues with the Kindle format. You might want to wait for that.
PDF is the best format for rendering, with no quality issues.
Enjoy DAX!
Should you use RANK or stick with RANKX?
In which scenarios is one better than the other?
Make an informed choice with this article + video!
#powerbi #dax
https://www.sqlbi.com/articles/using-rank-instead-of-rankx-in-dax/
In which scenarios is one better than the other?
Make an informed choice with this article + video!
#powerbi #dax
https://www.sqlbi.com/articles/using-rank-instead-of-rankx-in-dax/
December 2, 2025 at 11:04 AM
Should you use RANK or stick with RANKX?
In which scenarios is one better than the other?
Make an informed choice with this article + video!
#powerbi #dax
https://www.sqlbi.com/articles/using-rank-instead-of-rankx-in-dax/
In which scenarios is one better than the other?
Make an informed choice with this article + video!
#powerbi #dax
https://www.sqlbi.com/articles/using-rank-instead-of-rankx-in-dax/
If you are at PASS Summit 2025, look for me at the Tabular Editor booth in the Exhibit Hall.
I will show a sneak preview of DAX Optimizer basic edition: no emails, no data access, no external tools required.
The easiest way to verify if your semantic model can be optimized.
Coming soon...
I will show a sneak preview of DAX Optimizer basic edition: no emails, no data access, no external tools required.
The easiest way to verify if your semantic model can be optimized.
Coming soon...
November 19, 2025 at 5:22 PM
If you are at PASS Summit 2025, look for me at the Tabular Editor booth in the Exhibit Hall.
I will show a sneak preview of DAX Optimizer basic edition: no emails, no data access, no external tools required.
The easiest way to verify if your semantic model can be optimized.
Coming soon...
I will show a sneak preview of DAX Optimizer basic edition: no emails, no data access, no external tools required.
The easiest way to verify if your semantic model can be optimized.
Coming soon...
Learn the differences between model-dependent and model-independent DAX user-defined functions in this article+video.
Bonus: tips to publish libraries of functions on daxlib.org.
#dax #powerbi
https://www.sqlbi.com/articles/model-dependent-and-model-independent-user-defined-functions-in-dax/
Bonus: tips to publish libraries of functions on daxlib.org.
#dax #powerbi
https://www.sqlbi.com/articles/model-dependent-and-model-independent-user-defined-functions-in-dax/
November 18, 2025 at 11:03 AM
Learn the differences between model-dependent and model-independent DAX user-defined functions in this article+video.
Bonus: tips to publish libraries of functions on daxlib.org.
#dax #powerbi
https://www.sqlbi.com/articles/model-dependent-and-model-independent-user-defined-functions-in-dax/
Bonus: tips to publish libraries of functions on daxlib.org.
#dax #powerbi
https://www.sqlbi.com/articles/model-dependent-and-model-independent-user-defined-functions-in-dax/
Top 10 products are a classic. Reporting which products are in the top 10 for several years is more challenging.
We are looking for 𝗲𝘃𝗲𝗿𝗴𝗿𝗲𝗲𝗻 𝗽𝗿𝗼𝗱𝘂𝗰𝘁𝘀: how to find them in DAX in this article+video.
#powerbi #dax
https://www.sqlbi.com/articles/find-the-products-in-the-top-10-every-year-with-dax/
We are looking for 𝗲𝘃𝗲𝗿𝗴𝗿𝗲𝗲𝗻 𝗽𝗿𝗼𝗱𝘂𝗰𝘁𝘀: how to find them in DAX in this article+video.
#powerbi #dax
https://www.sqlbi.com/articles/find-the-products-in-the-top-10-every-year-with-dax/
November 4, 2025 at 11:04 AM
Top 10 products are a classic. Reporting which products are in the top 10 for several years is more challenging.
We are looking for 𝗲𝘃𝗲𝗿𝗴𝗿𝗲𝗲𝗻 𝗽𝗿𝗼𝗱𝘂𝗰𝘁𝘀: how to find them in DAX in this article+video.
#powerbi #dax
https://www.sqlbi.com/articles/find-the-products-in-the-top-10-every-year-with-dax/
We are looking for 𝗲𝘃𝗲𝗿𝗴𝗿𝗲𝗲𝗻 𝗽𝗿𝗼𝗱𝘂𝗰𝘁𝘀: how to find them in DAX in this article+video.
#powerbi #dax
https://www.sqlbi.com/articles/find-the-products-in-the-top-10-every-year-with-dax/
I start to believe that one of the biggest misconceptions in data analytics is that dimensional modeling is for the data warehouse, whereas it is really for the data mart.
Someone should fix that.
Someone should fix that.
October 25, 2025 at 9:18 AM
I start to believe that one of the biggest misconceptions in data analytics is that dimensional modeling is for the data warehouse, whereas it is really for the data mart.
Someone should fix that.
Someone should fix that.
Today you have one task: update DAX Studio to 3.4.0.
If you have a model with DAX UDFs (user-defined functions) or Calendars, here is the version that correctly handles autocompletion and VPAX export.
𝗘𝘅𝗽𝗼𝗿𝘁 𝘁𝗼 𝗣𝗮𝗿𝗾𝘂𝗲𝘁? Now you can!
https://daxstudio.org/blog/v3_4_0-release/
If you have a model with DAX UDFs (user-defined functions) or Calendars, here is the version that correctly handles autocompletion and VPAX export.
𝗘𝘅𝗽𝗼𝗿𝘁 𝘁𝗼 𝗣𝗮𝗿𝗾𝘂𝗲𝘁? Now you can!
https://daxstudio.org/blog/v3_4_0-release/
October 24, 2025 at 6:46 AM
Today you have one task: update DAX Studio to 3.4.0.
If you have a model with DAX UDFs (user-defined functions) or Calendars, here is the version that correctly handles autocompletion and VPAX export.
𝗘𝘅𝗽𝗼𝗿𝘁 𝘁𝗼 𝗣𝗮𝗿𝗾𝘂𝗲𝘁? Now you can!
https://daxstudio.org/blog/v3_4_0-release/
If you have a model with DAX UDFs (user-defined functions) or Calendars, here is the version that correctly handles autocompletion and VPAX export.
𝗘𝘅𝗽𝗼𝗿𝘁 𝘁𝗼 𝗣𝗮𝗿𝗾𝘂𝗲𝘁? Now you can!
https://daxstudio.org/blog/v3_4_0-release/
This article+video describes when to use VALUES in the table grouped by SUMMARIZE, also mentioning why SUMMARIZECOLUMNS does not have that option.
#powerbi #dax
https://www.sqlbi.com/articles/using-values-in-summarize/
#powerbi #dax
https://www.sqlbi.com/articles/using-values-in-summarize/
October 21, 2025 at 10:04 AM
This article+video describes when to use VALUES in the table grouped by SUMMARIZE, also mentioning why SUMMARIZECOLUMNS does not have that option.
#powerbi #dax
https://www.sqlbi.com/articles/using-values-in-summarize/
#powerbi #dax
https://www.sqlbi.com/articles/using-values-in-summarize/
Yesterday at dataMinds.be I asked the audience how many experienced disk defrag.
I was talking about Delta/Parquet files in DirectLake.
>50% raised their hands.
Next time, I'll ask about index rebuild on SQL Server.
We are so back.
I was talking about Delta/Parquet files in DirectLake.
>50% raised their hands.
Next time, I'll ask about index rebuild on SQL Server.
We are so back.
October 8, 2025 at 10:16 AM
Yesterday at dataMinds.be I asked the audience how many experienced disk defrag.
I was talking about Delta/Parquet files in DirectLake.
>50% raised their hands.
Next time, I'll ask about index rebuild on SQL Server.
We are so back.
I was talking about Delta/Parquet files in DirectLake.
>50% raised their hands.
Next time, I'll ask about index rebuild on SQL Server.
We are so back.
Spoiler: 800+ pages.
Not ready to announce the official release date yet, but the third edition of The Definitive Guide to DAX has broken the 800-page barrier.
But hey, there are many figures!
Coming soon...
Not ready to announce the official release date yet, but the third edition of The Definitive Guide to DAX has broken the 800-page barrier.
But hey, there are many figures!
Coming soon...
October 4, 2025 at 10:02 AM
Spoiler: 800+ pages.
Not ready to announce the official release date yet, but the third edition of The Definitive Guide to DAX has broken the 800-page barrier.
But hey, there are many figures!
Coming soon...
Not ready to announce the official release date yet, but the third edition of The Definitive Guide to DAX has broken the 800-page barrier.
But hey, there are many figures!
Coming soon...
I will be speaking live about UDF on Analytics Endeavors' channel on October 8 (morning in the US, late afternoon in Europe).
Set a reminder!
#dax #usd #live #powerbi
Set a reminder!
#dax #usd #live #powerbi
User-defined functions [UDFs] in DAX (With Marco Russo)
DESCRIPTION 📄In September 2025, Microsoft introduced a new feature in Power BI and in the DAX language: the ability to create user-defined functions (UDFs)....
www.youtube.com
September 30, 2025 at 4:28 PM
Simon Sabin and I sit down and chat to answer one simple question: why bother with conferences in 2026?
In the chat, we talk about meeting peers, asking real questions, and learning from battle-tested content (not vendor demos).
Watch (or just listen to) the video:
https://youtu.be/zwGDfL-B3jQ
In the chat, we talk about meeting peers, asking real questions, and learning from battle-tested content (not vendor demos).
Watch (or just listen to) the video:
https://youtu.be/zwGDfL-B3jQ
September 27, 2025 at 7:34 AM
Simon Sabin and I sit down and chat to answer one simple question: why bother with conferences in 2026?
In the chat, we talk about meeting peers, asking real questions, and learning from battle-tested content (not vendor demos).
Watch (or just listen to) the video:
https://youtu.be/zwGDfL-B3jQ
In the chat, we talk about meeting peers, asking real questions, and learning from battle-tested content (not vendor demos).
Watch (or just listen to) the video:
https://youtu.be/zwGDfL-B3jQ
I will be delivering a "Mastering DAX" Workshop in Lugano, Switzerland, from October 28-30, 2025.
This workshop is also near Northern Italy, France, and Southern Germany.
The workshop is in English.
For more details, visit: https://www.sqlbi.com/p/mastering-dax-workshop-lugano-oct-28-30-2025/
This workshop is also near Northern Italy, France, and Southern Germany.
The workshop is in English.
For more details, visit: https://www.sqlbi.com/p/mastering-dax-workshop-lugano-oct-28-30-2025/
September 25, 2025 at 8:31 AM
I will be delivering a "Mastering DAX" Workshop in Lugano, Switzerland, from October 28-30, 2025.
This workshop is also near Northern Italy, France, and Southern Germany.
The workshop is in English.
For more details, visit: https://www.sqlbi.com/p/mastering-dax-workshop-lugano-oct-28-30-2025/
This workshop is also near Northern Italy, France, and Southern Germany.
The workshop is in English.
For more details, visit: https://www.sqlbi.com/p/mastering-dax-workshop-lugano-oct-28-30-2025/
Watch a 30-minute chat with Jay recorded at FabCon25 Europe this week.
@jaypowerbi.sky.social is the product manager of DAX.
We talk about the new features just released: User-defined functions (UDFs) and Calendar-based time intelligence.
#dax #fabconeurope25
@jaypowerbi.sky.social is the product manager of DAX.
We talk about the new features just released: User-defined functions (UDFs) and Calendar-based time intelligence.
#dax #fabconeurope25
DAX UDFs and Calendar-based time intelligence: A chat with Jay
Here is a chat with Jeroen (Jay) ter Heerdt, the product manager for DAX, talking about the new features released today: User-defined functions (UDFs) and Ca...
youtu.be
September 20, 2025 at 8:16 AM
Watch a 30-minute chat with Jay recorded at FabCon25 Europe this week.
@jaypowerbi.sky.social is the product manager of DAX.
We talk about the new features just released: User-defined functions (UDFs) and Calendar-based time intelligence.
#dax #fabconeurope25
@jaypowerbi.sky.social is the product manager of DAX.
We talk about the new features just released: User-defined functions (UDFs) and Calendar-based time intelligence.
#dax #fabconeurope25
We finally have 𝘂𝘀𝗲𝗿-𝗱𝗲𝗳𝗶𝗻𝗲𝗱 𝗳𝘂𝗻𝗰𝘁𝗶𝗼𝗻𝘀 (𝗨𝗗𝗙) in DAX!
Don't make mistakes; this is not a user data function in Fabric.
This is a new DAX feature, the most important one in the last five years.
Read/watch more:
https://www.sqlbi.com/articles/introducing-user-defined-functions-in-dax/
Don't make mistakes; this is not a user data function in Fabric.
This is a new DAX feature, the most important one in the last five years.
Read/watch more:
https://www.sqlbi.com/articles/introducing-user-defined-functions-in-dax/
September 16, 2025 at 9:11 AM
We finally have 𝘂𝘀𝗲𝗿-𝗱𝗲𝗳𝗶𝗻𝗲𝗱 𝗳𝘂𝗻𝗰𝘁𝗶𝗼𝗻𝘀 (𝗨𝗗𝗙) in DAX!
Don't make mistakes; this is not a user data function in Fabric.
This is a new DAX feature, the most important one in the last five years.
Read/watch more:
https://www.sqlbi.com/articles/introducing-user-defined-functions-in-dax/
Don't make mistakes; this is not a user data function in Fabric.
This is a new DAX feature, the most important one in the last five years.
Read/watch more:
https://www.sqlbi.com/articles/introducing-user-defined-functions-in-dax/
Read our first article and watch the video about the new calendar-based time intelligence feature in DAX and Power BI.
Helpful for Gregorian, necessary for non-Gregorian calendars.
#powerbi #dax #timeintelligence
https://www.sqlbi.com/articles/introducing-calendar-based-time-intelligence-in-dax/
Helpful for Gregorian, necessary for non-Gregorian calendars.
#powerbi #dax #timeintelligence
https://www.sqlbi.com/articles/introducing-calendar-based-time-intelligence-in-dax/
September 16, 2025 at 8:26 AM
Read our first article and watch the video about the new calendar-based time intelligence feature in DAX and Power BI.
Helpful for Gregorian, necessary for non-Gregorian calendars.
#powerbi #dax #timeintelligence
https://www.sqlbi.com/articles/introducing-calendar-based-time-intelligence-in-dax/
Helpful for Gregorian, necessary for non-Gregorian calendars.
#powerbi #dax #timeintelligence
https://www.sqlbi.com/articles/introducing-calendar-based-time-intelligence-in-dax/