title: sum across a row in sql
body: <p>I want to sum the values of Punten1,Punten 2,Punten 3,Punten4 as a total.
  But I only know how to sum the values across the column. But not across the row.
  Does anyone know how to do this.    </p>
  
  <pre><code>SELECT Punten1, Punten2, Punten3, Punten4
  Punten1 + Punten 2 + Punten3 + Punten4 as Puntentotaal
  FROM puntentotaal
  </code></pre>
  
  <p>So i would like to sum  the values of Punten1,Punten 2,Punten 3,Punten4 in a new column: puntentotaal
  thanks!</p>