PowerQuery: How can I concatenate grouped values? : <p>If I have the following table (shown in the image below), how can I write a grouped query that would concatenate the grouped results?</p>

<p><a href="https://i.stack.imgur.com/FwYeH.png" rel="noreferrer"><img src="https://i.stack.imgur.com/FwYeH.png" alt="InputTable"></a></p>

<p>For this example, I'd want to group by the <code>LetterColumn</code> and concatenate the <code>NumberColumn</code></p>

<p>So the desired results would be:</p>

<p><a href="https://i.stack.imgur.com/0rQwR.png" rel="noreferrer"><img src="https://i.stack.imgur.com/0rQwR.png" alt="ResultsTable"></a></p>
