If you have read the book Alberto and I wrote, “The Definitive Guide to DAX” then by looking at the title you might think that this post is about the book. Not this time. I am talking about the new…  Read more

Estimating the cardinality of iterators is an important skill when optimizing DAX code. This article explains how to use this technique, evaluating different ways of computing the number of working days between two dates.  Read more

This article describes possible optimization approaches to improve the performance of nested iterators in DAX.  Read more

DAX Studio connects to a Power BI Desktop model using a technique that was not officially supported until a few months ago. This changed when the “diagnostic port” was documented in this article of the official documentation:  Read more

DAX supports dates starting in 1900 and while teaching DAX I always explain that DAX manages dates like Excel, which is the reason why these limitations exist. Actually, this is true – but answering to a comment today I realized…  Read more

The Sort By Column feature in Power BI causes side effects that are important to know when writing a DAX formula. This article explains these side effects and how to write correct DAX code to avoid getting incorrect results.  Read more

How can you optimize your DAX expressions? In this session, we’ll analyze DAX expressions and Tabular models, then utilize DAX Studio and the VertiPaq model to explore how to optimize them. While most optimizations are the direct application of best…  Watch now

This article describes how to use the detail rows expression of a measure to obtain the equivalent of creating table functions in DAX. This allows the reusing of a table expression in multiple CALCULATE filters.  Read more

By answering to a student question I realized we often used a wrong calculation of customers age in DAX, and the simple solution is to borrow the same technique used in Excel, using INT and YEARFRAC rather than DATEDIFF or…  Read more

I received a question about how to implement the equivalent of a DISTINCTCOUNTX function in DAX. Well, such a function doesn’t exist in DAX, but imagine you want to write something like: The corresponding measure working in DAX is: In…  Read more