When to use SUM vs SUMX in DAX

It has been a long time since my last blog post. I have been very busy lately writing my new book "Learn to Write DAX - A Practical Guide to Learning Power Pivot for Excel". I have to get this to the publisher by the end of this month and it is scheduled for release in November 2015. This book is specifically written to help Excel users get started with DAX and is based on my experience teaching DAX in live training classes over the last 12 months. Once you have read the book and completed the exercises, you will be well on your way to becoming a DAX and Power Pivot ninja. If you are interested in registering to stay updated when this book is available to purchase, there is a registration box at the bottom of the page.