title: How can I aggregate on 2 dimensions in Google Data Studio?
body: <p>I have data in 2 dimensions (let's say, time and region) counting the number of visitors on a website  for a given day and region, as per the following:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>time</th>
  <th>region</th>
  <th>visitors</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>2021-01-01</td>
  <td>Europe</td>
  <td>653</td>
  </tr>
  <tr>
  <td>2021-01-01</td>
  <td>America</td>
  <td>849</td>
  </tr>
  <tr>
  <td>2021-01-01</td>
  <td>Asia</td>
  <td>736</td>
  </tr>
  <tr>
  <td>2021-01-02</td>
  <td>Europe</td>
  <td>645</td>
  </tr>
  <tr>
  <td>2021-01-02</td>
  <td>America</td>
  <td>592</td>
  </tr>
  <tr>
  <td>2021-01-02</td>
  <td>Asia</td>
  <td>376</td>
  </tr>
  <tr>
  <td>...</td>
  <td>...</td>
  <td>...</td>
  </tr>
  <tr>
  <td>2021-02-01</td>
  <td>Asia</td>
  <td>645</td>
  </tr>
  <tr>
  <td>...</td>
  <td>...</td>
  <td>...</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>I would like to create a table showing the average daily worldwide visitors for each month, that is:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>time</th>
  <th>visitors</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>2021-01</td>
  <td>25238</td>
  </tr>
  <tr>
  <td>2021-02</td>
  <td>16413</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>This means, I need to aggregate the data this way:</p>
  <ul>
  <li>first, sum over regions for distinct dates</li>
  <li>then, calculate average on dates</li>
  </ul>
  <p>Is was thinking of doing a global average of all lines of data for each month, and then multiply the value by the number of days in the month but since that number is variable I can't do it.</p>
  <p>Is there any way to do this ?</p>