title: Why order_by() doesn't work in codeigniter?
body: <p>why not worked <code>order_by</code> in <code>codeigniter</code>?</p>
  
  <pre><code>$this-&gt;db-&gt;order_by("id", "desc")-&gt;query('SELECT @rownum:=@rownum+1 rownum, t.* FROM (SELECT @rownum:=0) r, hotel_submits t');
  </code></pre>