title: show row number in select query
body: <p>what is the problem with this query? it shows null in rowno column.</p>
  
  <pre><code>SELECT @rowno:=@rowno+1 `rn`,`id`, `title`, `topic` 
  FROM stories,(SELECT @rownum:=0) r 
  WHERE newstype='2';
  </code></pre>
  
  <p>i run it in 'MySQL Query browser'</p>
  
  <p>thanks in advance.</p>