Allow aggregation of text when doing Group By in PowerQuery
When doing Group By it is possible to choose an aggregation but it is not possible to do Text Aggregation (using concatenation) using the UI.
It is possible to aggregate strings using "Text.Combine" in the advanced editor but it is a common enough operation that I think it should be added to the user interface.
See https://excelgorilla.com/power-bi/power-query/aggregate-text-values-using-group-by/ for an example of doing it in the advanced editor.
Chris Britton commented
This is definitely useful for collapsing multiple rows where values differ only in a single column into a single row with a delimited list of textual values (e.g. CSV). As the original suggestion highlights, the work-around is to group by selecting the sum aggregation function and then manually overriding the generated M query to perform Text.Combine instead.