title: Receiving an "Undefined index" notice when wanting to sum in a mysql query
body: <p>I'm trying to get the sum of a column from my database. When I try this code I get the error <code>Undefined index: sum(col_1)</code>. How can I do this? I'm a real beginner so keep it a bit simple.</p>
  
  <pre><code>$sql = "SELECT * FROM table_1";
  $run = mysqli_query($conn, $sql);
  while($rows = mysqli_fetch_assoc($run)){
      $col_ans[1] = $rows['sum(col_1)'];
          echo $col_ans[1];
      }
  </code></pre>