title: SQL: How to track point changes in the table
body: <p>I have a table where points change daily. I need to track how many points change on daily basis. 
  For Eg:</p>
  
  <pre><code>    Date         PointsWon
      2018-03-20     4567
      2018-03-19     4513
      2018-03-18     3879
  </code></pre>
  
  <p>What would be an easy way to do this? </p>