This video is a wild one! To make running totals in native Excel is pretty easy. However, in this video, you will see the adventure for making Running Totals in Power Query (Get and Transform).
You will see some M Coding in Power Query, Lists, List.Range, List.Sum, custom columns, and putting an entire table inside a single column.
In Excel we can work at the cell level and that’s what makes running totals easy. But, in Power Query, we have to work on entire rows or columns. So, there are a lot of steps to force Power Query to give us what we want.
For an intro to Get & Transform (Power Query) try my Lynda.com course:
My book: Guerrilla Data Analysis 2nd Edition
My old blog: http://datascopic.net/blog-2-2