title: MongoDB aggregation transformation
body: <p>I have a MongoDB, which is used in <em>Redash</em> to query some data. For a Funnel i want to display via Redash i have a MongoDB query that results in something like this</p>
  <pre><code>X   Y   Z
  20  10  35
  </code></pre>
  <p>But actually the Funnel Chart in Redash requests a table that looks like</p>
  <pre><code>State  Value
  X      20
  Y      10
  Z      35
  </code></pre>
  <p>How can i extend my MongoDB aggregation to get the wanted result? Maybe just manually create the needed rows? How to do that?</p>