title: Google Data Studio - Custom Aggregation formula
body: <p>I am building a report in Google Data Studio, and I run into a problem with the aggregation for a couple of metrics.</p>
  
  <p>As an example, I have the following table:</p>
  
  <pre><code>name. |. M1. |. M2. |. M3
    A.     23     45     1,9
    B.     45     6      0,1
    C.     23     45     1,9
    D.     12     34     2,8
    E.     4      2      0,5
  </code></pre>
  
  <p>Where </p>
  
  <pre><code>M3 = M2/M1
  </code></pre>
  
  <p>Now, when I display this in a table in GDS, the totals for M1 and M2 are the sum of the values, and that is ok, but I can only choose between fixed aggregation operations, and the total for M3 should be:</p>
  
  <pre><code>Total M3 = sum(M2)/sum(M1)
  </code></pre>
  
  <p>Any idea if this is possible?</p>