Introduction to the second edition

When we decided it was time to update this book, we thought it would be an easy job: After all, not many things have changed in the DAX language, and the theoretical core of the book was still very good. We believed the focus would mainly be on updating the screenshots from Excel to Power BI, adding a few touch-ups here and there, and we would be done. How wrong we were!

As soon as we started updating the first chapter, we quickly discovered that we wanted to rewrite nearly everything. We felt so not only in the first chapter, but at every page of the book. Therefore, this is not really a second edition; it is a brand new book.

The reason is not that the language or the tools have changed so drastically. The reason is that over these last few years we—as authors and teachers—have evolved a lot, hopefully for the better. We have taught DAX to thousands of users and developers all around the world; we worked hard with our students, always striving for the best way to explain complex topics. Eventually, we found different ways of describing the language we love.

We increased the number of examples for this edition, showing practical uses of the functionalities after teaching the theoretical foundation of DAX. We tried to use a simpler style, without compromising on precision. We fought with the editor to increase the page count, as this was needed to cover all the topics we wanted to share. Nevertheless, we did not change the leitmotif of the book: we assume no previous knowledge of DAX, even though this is not a book for the casual DAX developer. This is a book for people who really want to learn the language and gain a deep understanding of the power and complexity of DAX.

Yes, if you want to leverage the real power of DAX, you need to be prepared for a long journey with us, reading the book from cover to cover, and then reading it again, searching for the many details that—at first sight—are not obvious.