Re: Why is NULL = unbounded for rangetypes?

<div>På mandag 08. juli 2013 kl. 19:16:15, skrev Jeff Davis &lt;<a href="mailto:pgsql(at)j-davis(dot)com" target="_blank">pgsql(at)j-davis(dot)com</a>&gt;:</div>

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<div style="display:inline; font-family: monospace; font-size: 12px;">On Mon, 2013-07-08 at 10:19 +0200, Andreas Joseph Krogh wrote:<br>
&gt; Hi.<br>
&gt; <br>
&gt; Both of these queries return TRUE because NULL means &quot;unmounded&quot;:<br>
&gt; select daterange('2013-07-01' :: DATE, null, '[]') &amp;&amp; daterange('2013-07-04' :: DATE, '2013-07-30' :: DATE, '[]');<br>
&gt; select daterange(null, '2013-08-11' :: DATE, '[]') &amp;&amp; daterange('2013-07-04' :: DATE, '2013-07-30' :: DATE, '[]');<br>
&gt; What is the rational behind this behavior of NULL?<br>
<br>
It's just a convenience that passing NULL to a constructor creates an<br>
unbounded range. The alternatives of having extra constructors for<br>
unbounded ranges were discussed, but seemed more awkward.<br>
<br>
Note that ranges do not allow either bound to be NULL. That would create<br>
a lot of semantic problems.<br>
<br>
Does that answer your question?</div>
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<div>I would expect the queries above to return FALSE and have to use INFINITY to have them return TRUE. I don't understand what you mean by ranges not allowing either bound to be NULL as it seems to be the case (as in &quot;it works&quot;).</div>

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Andreas Joseph Krogh &lt;andreak(at)officenet(dot)no&gt;      mob: +47 909 56 963<br>
Senior Software Developer / CTO - OfficeNet AS - http://www.officenet.no<br>
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