If you’re a Power BI fan there are three possible answers to the question “Did you know that the second edition of The Definitive Guide To DAX has just been published?”:
Answer#1: Yup, I’ve already got my copy!
If this is your answer there’s no need to read any further.
Answer #2: What’s “The Definitive Guide To DAX”?
If, on the other hand, you’re new to Power BI and this is what you’re thinking then I should explain that “The Definitive Guide To DAX” is a book by Marco Russo and Alberto Ferrari and is what its title suggests it is – the sum total of human knowledge about the DAX calculation and query language used by Power BI, written by the two people who know most about it outside the development team. Marco and Alberto are friends of mine but I don’t think anyone can accuse me of bias when I say that it’s a book that every Power BI developer needs to own, so go out and buy it! If you use Power BI you need to learn DAX and while this book may not be a simple step-by-step tutorial it has in it somewhere answers to just about every question you’ll ever ask about DAX – and, more importantly, the answers it has are as correct and as up-to-date as they possibly can be. I can tell you that it’s proved invaluable to me in my work at least twice in the last week alone.
Answer #3: Yes, I saw that but I already have the first edition – is it worth buying this one too?
This is a slightly more difficult question to answer, but I’m still going to recommend that you buy the second edition. As Marco says in his announcement blog post, a lot of the existing content has been updated and rewritten and a lot of new content has been added. If you care about following all the latest DAX best practices and you don’t want the new hire in your department to mock you because you’ve never heard of DAX Studio, you need to buy this new edition.
[Note: I didn’t get a free copy of this book for review (yet?) but I have an O’Reilly Online Learning account which means I could read it as soon as it was published]
PS I know someone needs to write the “Definitive Guide to M” but it’s not going to be me, at least not right now.