谢谢各位，只能这样了：）<br><br><div class="gmail_quote">2008/12/4 smallfish <span dir="ltr">&lt;<a href="mailto:smallfish@live.cn">smallfish@live.cn</a>&gt;</span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
只能用<br>
SELECT (unix_timestamp(now()) - unix_timestamp(starttime)) as diff FROM `workers` WHERE （unix_timestamp(now()) - unix_timestamp(starttime)) &lt; 900;<br>
<br>
where里是不能用前面as的名字<br>
<br>
--------------------------------------------------<br>
From: &quot;Fayland Lam&quot; &lt;<a href="mailto:fayland@gmail.com" target="_blank">fayland@gmail.com</a>&gt;<br>
Sent: Thursday, December 04, 2008 2:44 PM<br>
To: &lt;<a href="mailto:china-pm@pm.org" target="_blank">china-pm@pm.org</a>&gt;<br>
Subject: Re: [PerlChina] 有个SQL 查询，出错了。着急问一下结果<div><div></div><div class="Wj3C7c"><br>
<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
rorot wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
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<br>
FROM `workers` WHERE diff &lt; 900;<br>
</blockquote>
<br>
sounds like you want HAVING. you can&#39;t use SELECT result to be a WHERE.<br>
it&#39;s not logic sane.<br>
<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br>
上面这条MySQL查询为什么出错？？<br>
<br>
*MySQL said: *Documentation<br>
&lt;<a href="http://dev.mysql.com/doc/refman/5.0/en/error-messages-server.html" target="_blank">http://dev.mysql.com/doc/refman/5.0/en/error-messages-server.html</a>&gt;<br>
<br>
| #1054 - Unknown column &#39;diff&#39; in &#39;where clause&#39; |<br>
<br>
<br>
<br>
rorot Dec/04/2008<br>
<br>
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</blockquote>
<br>
<br>
-- <br>
Fayland Lam // <a href="http://www.fayland.org/" target="_blank">http://www.fayland.org/</a><br>
Foorum based on Catalyst // <a href="http://www.foorumbbs.com/" target="_blank">http://www.foorumbbs.com/</a><br>
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</blockquote>
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