title: Summing values in two columns based on a single userId
body: <p>How can I combine data if userIdA and userIdB are the same. The result would be the data stored in userId, ValA, and    ValB</p>
  
  <pre><code>ValA        userIdA   ValB  userIdB     userId  ValA    ValB
  2           1227      16    1025        1227    2       17
  12          1251      40    1213        1251    12      44
  1           1279      17    1227                
  7           1452      44    1251                
  2           1466      16    1261    
  </code></pre>