title: I would like to create an efficient Bigtable row key
body: <p>I would like to create an optimal row key in Bigtable. I have a table <code>channel_data</code> with 3 columns: <code>channel_id</code>,<code>date</code>,<code>fan_count</code>.</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>channel_id</th>
  <th>date</th>
  <th>fan_count</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>1</td>
  <td>2022-03-01</td>
  <td>5000</td>
  </tr>
  <tr>
  <td>1</td>
  <td>2022-03-02</td>
  <td>6000</td>
  </tr>
  <tr>
  <td>2</td>
  <td>2022-03-01</td>
  <td>200</td>
  </tr>
  <tr>
  <td>2</td>
  <td>2022-03-02</td>
  <td>300</td>
  </tr>
  <tr>
  <td>3</td>
  <td>2022-03-03</td>
  <td>1000</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>Users of our application can set up brands/buckets by adding multiple channels. Users can choose any random <code>channel_id</code>.</p>
  <p>I want to design an efficient row key to fetch aggregated <code>fan_count</code> in a date range for a brand.</p>
  <p>Let's say the user creates a brand with <code>channel_id</code> 1 and 3 and wish to see sum of all fans for the time period 2022-03-01 to 2022-03-03</p>
  <p>The result should be 5000+6000+1000=12000</p>