What is DAX? A Three Minute Overview
Data Analysis Expressions — Some Context and Iteration
Have you heard of DAX? Of course, you have. It is only a matter of which one? Are you into motor bikes? The YouTuber? Deep Space 9? Apparel conventions? The German Stock Market? Or animate bugs…?
If you are a Power BI or Power Pivot user, you may have a different understanding of DAX.
DAX — Data Analysis Expressions
But what exactly are data analyis expressions? Good question. Let’s break it down.
First of all, it is very functional. You can take that several different ways, most will prove true. But in DAX — expressions take the form of functions.
Second of all, it is tabular. DAX functions act upon tables. Its functions connect, iterate, and aggregate.
Third, it is relational. Again, that could have numerous contexts. Feel free to use most of them. Relationships and context feature prominently.
Is all this semantics?
Yes, yes it is. DAX is a component of the BI Semantic Model. That makes it related to both SQL and MDX. It is a set of functional expressions used to connect disparate data across mostly tabular data models. If that seems overly simple or the exact opposite, you aren’t far off. Simple protocols for complicated concepts.
So this is a Microsoft thing?
Yes, that is true. DAX began about a decade ago as a component of Power Pivot. But in the last few years has expanded to more products and more dimensions. With the recent arrival of Power BI as a top flight tool, DAX has become quite popular… or has it?
Many BI tools seek to wrap drag-and-drop, point-and-click user interfaces around their inner engines. Embedded query languages like DAX can be polarizing. Witness the rise of non-SQL database structures. They generated large amounts of love and hatred.
Much like SQL, DAX has a loyal base who value the power and simplicity of functional query languages. Much like SQL, DAX requires a decent amount of experience and discipline to do it right. To those who have not learned the language, it is a difficult gatekeeper blocking them from data access.
Two sides of the coin
Whichever side you are on, DAX is another tool in the toolbox. It is also another set of conventions and contexts. If you never work in the Microsoft sphere, you can probably just ignore it. Plenty of equally great (and annoying) tools exist in other BI solutions (set notation anyone?).
As an educator, you need to respect a language that provides a functional perspective on some sometimes difficult and often ignored concepts. As an analytics executive, I can tell you it is a resume item I would have looked for at any time in my career. My teams were not always Microsoft shops (though they were at times), but strong DAX skills would signal a greater analytic discipline that I would have valued in most employees.
For those interested in learning more, SQLBI has one of the better offering that I found. I recommend learning DAX as part of a more integrated and foundational offering, but few such offerings are in market, yet…
Thanks for reading!
