I have finished reading the book about a week ago, this post is partly a review of the book and also about my journey of studying DAX.
First let me inform you that I read the 1st edition and the 2nd edition is scheduled to be published on 6th August 2018 so you might decide to wait for that one.
It is a book worth buying and reading but I think it is better understandable if you read another book about DAX first that covers the basic or intermediate topics.
Some of you might think that reading about DAX is not necessary because you can google or bing your problems individually and use the suitable DAX function. Sometimes you will need to combine 5 or more DAX functions to solve the particular problem so it is very important to have a deep understanding of data models, the filter contexts and your decisions’ effects on performance.
Hey, I have just searched the word “Power” in my Kindle library.
I really recommend reading Power Pivot and Power BI from Rob Collie and Avichal Singh first. It is better for beginners. Check out the blog of the authors PowerpivotPro !
The book has downloadable sample files and a database to practice with.
I like the results of the DAX expressions shown in pictures and that the authors really wanted to make sure that I understand the logic of the most useful DAX formulas and data models. I think this is the book that should introduce you to the CALCULATE, FILTER, RELATED and other important functions. Most of the book is applicable to Power BI and the Power Pivot topics are also important to understand because you might need it to solve a problem in Excel. When I need to refresh my DAX knowledge this is the book I scroll through first.
The Definitive Guide To DAX
This one also has downloadable content. The topics of this book gets very often very complicated so you should accept that you won’t understand everything by reading it once. I plan to read it once a year. It is a long book, almost 600 pages so it is okay if you don’t understand every DAX function the book writes about. DAX is a programming language and also a querying language like SQL, the latter is much less frequently used so focus on the programming topics that are describing ways to create calculated columns and measures.
The one topic that you should really understand is the filter propagation, filter contexts such as the row context and filter context because that plays an important role in creating measures or calculated columns.
You should write a reading journal of the book in which you can organize your notes, links to useful blogposts and DAX functions you find online. Writing this journey takes took time because there were very interesting and complicated topics where I typed a lot but it is a good investment of your time because you can’t remember everything you read in this 600 pages long book.
The authors have a https://www.daxpatterns.com/ website which they published in a book form also. You should check it out also!