title: Count rows with certain condition and still show all rows
body: <p>My table looks like this:</p>
  
  <pre><code>col1      col2
  Denmark   Yes
  Denmark   No
  Denmark   Yes
  Brazil    Yes
  Brazil    No
  Brazil    No
  </code></pre>
  
  <p>I want to count the distinct countries and tally the number of <code>Yes</code> in a separate column. For example:</p>
  
  <pre><code>col3      col4
  Denmark   2
  Brazil    1
  </code></pre>
  
  <p>What is the best way to count all the <code>'Yes'</code> and show all the distinct countries from <code>col1</code>?</p>