title: How to have pie chart count based on distinct values of a column in Tableau?
body: <p>In a database table I have something like this:</p>
  
  <pre><code>RatingID, StudentID, Sport, Rating
  1, 1,     Tennis, 2
  2, 1,     Tennis, 5
  3, 2,     Basketball, 2
  4, 2,     Basketball, 5
  5, 3,     Basketball, 2
  </code></pre>
  
  <p>I want a pie chart that counts up how many people are playing each sport.
  Currently, I am getting a pie chart using "Sport" that says:</p>
  
  <pre><code>BasketBall: 3
  Tennis: 2
  </code></pre>
  
  <p>When I attempt to do a Distinct(SPORT), it says 1 for both. 
  What I want to do is to be able to do a distinct on StudentID such that the pie chart says:</p>
  
  <pre><code>Tennis: 1
  Basketball: 2
  </code></pre>
  
  <p>How can I do this? Is it possible?</p>