Now and again the question is raised on the forum on how to learn more about M. Tips for other online resources, books, video’s and so on. To centralize all these bits and pieces of information @BrianJ rightfully suggested to post it here and make it easier for anyone to find and contribute
My ‘general’ Best practices for how to expand your knowledge on Power Query M are:
- Make sure to have the Formula Bar visible in Power Query at all times. That way you can see the M code that’s generated by the UI and get you more familiar with it’s syntax.
- Formula Language Specification Describes the structure of the language. Make a habit of revisiting it after you’ve practiced for some time - things will start to make more sense…
- Formula Reference Bookmark this page. All functions with their specs. Read them, copy the example codes, paste it into the formula bar or advanced editor and study the results
- The Standard Library in Power Query itself which lists all built-in functions:
#shared keyword can be used to list all the functions available and
a function name without brackets can be entered to see it’s documentation
- Introduction to M an hour long video by Chris Webb, a must see in my opinion!
- Practice, practice, practice. Probably the most important thing when learning something new.
For a practical approach: “Collect, Combine And Transform Data Using Power Query In Excel And Power BI” by Gil Raviv
If you have something to add, please share it with this community by replying to the tread.
Just like in Excel or with DAX there are often multiple ways to solve a problem and the same is true for Power Query. At the moment I like to use the UI as much as possible and only modify the M code when I need to. That way I hardly ever have to write M and that makes it easier to follow along.
But remember, there are alternatives - so don’t forget to explore on your own and report back.