title: Google Data Studio: Chart Calculated Field Invalid Formula
body: <p>I'm building a report in GDS and I'm trying to take advantage of the new Chart Calculate Field.</p>
  
  <p>I have the following data</p>
  
  <pre><code>unique_users    120,449
  clicks          4,405
  </code></pre>
  
  <p>I want to calculate the CTR using this formula:</p>
  
  <pre><code>SUM(clicks) / SUM(unique_users)
  </code></pre>
  
  <p>I keep getting an invalid formula error which I don't understand (attached is a screenshot).</p>
  
  <p><a href="https://i.stack.imgur.com/VkGxL.png" rel="noreferrer"><img src="https://i.stack.imgur.com/VkGxL.png" alt="enter image description here"></a></p>
  
  <p>The columns I'm trying to calculate comes from a blended data, this is its definition:</p>
  
  <p><strong>unique_user</strong></p>
  
  <p><a href="https://i.stack.imgur.com/5MTqv.png" rel="noreferrer"><img src="https://i.stack.imgur.com/5MTqv.png" alt="enter image description here"></a></p>
  
  <p><strong>clicks</strong></p>
  
  <p><a href="https://i.stack.imgur.com/Nn7az.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Nn7az.png" alt="enter image description here"></a></p>