I have been waiting for this book Power Query for Power BI and Excel by Chris Webb for some time and I am pleased to advise it is a great book for a broad range of people with anything from zero to medium skills in Power Query. I fall into the later category and I found some value in every chapter, with increasing value per chapter as the book progressed.
Chris has written this book in a thoughtful manner. He starts with the basics and then layers concepts one on one until he culminates with a chapter of real world examples of easy to understand use cases. These use cases leverage the skills learnt in the book and give you something meaningful to work on to absorb how the concepts are used in real life. I am confident that with these new skills I will be able to accelerate my self learning using the book as a reference along with the other resources provided by Chris as links in the book.
Chapter 1 is a good overview for people that are new to Power Query. Anyone that has used the tool a bit won’t find much here. There is however a good section on licensing that clearly describes what products come with each licensing purchase.
Chapter 2 takes you through each data source format one at a time, and gives examples of each. You could do this yourself with a bit of trial and error, but it is very convenient to have this as a reference. There is also an excellent reference about advance search functions to improve the quality of your searches over the web, and a great tip on referencing other Power Queries as a data source.
Chapter 3 is a comprehensive overview of the transform capabilities of Power Query. This would be very useful for newbies and a useful section to skim for those with a reasonable working knowledge to validate complete breadth of knowledge.
Chapter 4 focuses on what happens to the data when you return it to Excel and/or the data model including some tips on refreshing data.
Chapter 5: the M language! Chris writes this chapter to help you get the most out of these documents by explaining concepts not covered so well in the tech documents themselves, such as the Let statement. You are not going to be an M Language wizard after reading this chapter, but you can expect to have a much better understanding of the structure of the language, and how to make sense of the output generated from the user interface. With this base to build upon, you can learn more about M yourself much in the way that you can learn to program VBA from the Excel Macro Recorder.
Chapter 6 covers multiple tables. Building on what you have learnt about lists and the M language, the concepts of joining tables somehow doesn’t seem so hard now. I always struggled to get my head around the syntax before reading this chapter. The incremental build up to chapter 6 and the content of this chapter have sorted that out for me.
Chapter 7 extensively covers Power BI cloud integration, including sharing queries in the cloud, how to manage the quality of queries through certification, and some tips on how to manage version control. If you are using Power BI in your organisation, these will indeed be valuable information to get off on the right track.
Finally chapter 8 is the culmination of everything taught in the book. Chris gives step by step instructions on how to create specific transformations to data in real world use cases. He takes you through each step so that you learn what to do, then explains anything that needs further clarification. I would highly recommend actually doing each of the recipes on your own PC as a learning experience to cement your new knowledge.
All in all, a great purchase at under $20 for the eBook.