title: Count of non-null columns in each row
body: <p>I have a table that contains 4 columns and in the 5th column I want to store the count of how many non-null columns there are out of the previous 4. For example:</p>
  
  <p>Where X is any value:<br></p>
  
  <pre><code>Column1 | Column2 | Column3 | Column4 | Count
    X     |    X    |   NULL  |    X    |   3
   NULL   |   NULL  |    X    |    X    |   2
   NULL   |   NULL  |   NULL  |   NULL  |   0
  </code></pre>