title: #1221 - Incorrect usage of UPDATE and ORDER BY
body: <p>To bypass a problem I posted in a other thread. I tried an sql statement like this:</p>
  
  <pre><code>UPDATE user u JOIN (SELECT @i := 0) r
  SET user_rank_planets = (@i := (@i + 1))
  WHERE user_active=1
  ORDER BY user_planets DESC
  </code></pre>
  
  <p>I got Error #1221. Without the order by clause, the statement works fine.
  Is there someone who knows a solution for this issue?</p>