Foreword from Imke:
Pat Mahoney is a very active fellow super user in the Power BI community and has a very strong interest in all things Power Query. He also has a YouTube-channel with interesting videos about Power BI. Here he is sharing a nifty solution for a specific kind or parent-child-challenge which he solves with the List.Accumulate-function:

The need to know which inputs are related to which outputs (and vice versa) is a common business use case, whether it’s lots used in a multi-step manufacturing process, reporting relationships in an organization, or other scenarios. As organizational relationships are usually Many:1 (employees:supervisor), in Power BI a string showing the org hierarchy can be generated using the PATH function in DAX. However, supply chains (and many other scenarios) frequently have M:M relationships and a different solution is required. In this article, an M function that leverages List.Accumulate is described that generates such relationships from an input table that has input/output columns. This is not the first function/code to do this of course (see one of Imke’s posts on this subject), but the one shown here uses a different approach, gives an option of outputs, and provides another tool for the toolbox.
Read more

In a previous article I have described how to use Fuzzy merge to match misspelled data to valid categories. With the sample data at hand, all values could be matched to existing categories. But what can you do if there are some entries that cannot be matched to existing categories?

I would create an “unmatched” value to the categories table before loading to the data model and assign the “unmatched”-value to all unmatched entries. Then I would create a measure that counts the entries within the unmatched category. I would then create a data driven alert, based on this measure. That would trigger an e-mail to the person responsible for maintaining the list. Or, if responsibilities are a bit more complex, trigger a flow in Power Automate that could handle certain conditions to be followed as well.

Let’s look at some details:

Add an “unmatched” value to the categories table for exception reporting

First I select the category table and deselect “Enable load”, as I want to use this table only for the match. The table that shall be loaded to the model will contain the value for the unmatched items as well. Therefor I reference this query and create a new query. There I add a new row with the following formula:

Categories & #table({"Column1"}, {{"Unmatched"}})

Exception reporting for fuzzy matching

Replace unmatched values

Read more