Find the closest entry based on timestamp
<p>I have a table with entries about the weather every 20 minutes. For example, this would be the timestamp column:</p>

<pre><code>2007-01-01 00:00:00
2007-01-01 00:20:00
</code></pre>

<p>And so on. Now if I have another timestamp, for example <code>2007-01-01 00:07:53</code>, how can I find the entry within the weather table that is closest to this specific timestamp?</p>