Advanced transformations on multiple columns at once in Power BI and Power Query

You can apply simple transformations to multiple columns at once in Power Query using the UI only. In this article I show how you can apply advanced transformations on multiple columns at once instead. You can also use this to use custom functions instead. And lastly for the lazyefficient fans of custom M-functions: You will get a new “TranformAllMyColumnsAtOnceHowILikeIt”-function as well 😉

Background

The Transform-tab in the query editor is sensitive to the columns you select. So if you select multiple number columns for example, some number transformations will be greyed out and are therefore not accessible:

Some symbols are greyed out, Advanced transformations on multiple columns at once in Power BI and Power Query, Power BI, Power Query, Power BI Desktop

Some symbols are greyed out

So how could I then multiply all my columns by 10 for example, as the symbol for multiplication is greyed out? Read more