title: Join two columns in one columns codeigniter
body: <p>is this possible ? two columns in one columns on table ?</p>
  
  <pre><code>$this-&gt;db-&gt;select('header.*,customer.*,destination.location');
  $this-&gt;db-&gt;from(self::WAYBILL_HEADER_TABLE. " as header");
  $this-&gt;db-&gt;join(self::CUSTOMER_TABLE." as customer","header.consignee = customer.id");
  $this-&gt;db-&gt;join(self::WAYBILLDESTINATION_TABLE. " as destination","header.destination_from = destination.id",'INNER');
  
  $this-&gt;db-&gt;join(self::WAYBILLDESTINATION_TABLE. " as destinations","header.destination_to = destinations.id",'INNER');
  $this-&gt;db-&gt;where('header.waybilldate &lt;=',$date_to);
  $this-&gt;db-&gt;where('header.waybilldate &gt;=',$date_from);
  $this-&gt;db-&gt;order_by('header.waybillno','DESC');
  $query = $this-&gt;db-&gt;get()-&gt;result();
  return $query;
  </code></pre>