不好意思，着急用。刚才在SQL IRC里没人回答。所以发这里，望有人解决一下。<br><br>SELECT (unix_timestamp(now()) - unix_timestamp(starttime)) as diff&nbsp; FROM `workers` WHERE diff &lt; 900;<br><br>上面这条MySQL查询为什么出错？？<br><br><p>
    <strong>MySQL said: </strong><a href="http://dev.mysql.com/doc/refman/5.0/en/error-messages-server.html" target="mysql_doc"><img class="icon" src="http://www.youchela.com/mysql/themes/original/img/b_help.png" alt="Documentation" title="Documentation" width="11" height="11"></a>
</p>
<code>
#1054 - Unknown column &#39;diff&#39; in &#39;where clause&#39;
</code><br><br><br><br>rorot Dec/04/2008<br>
<br>