Why is NULL = unbounded for rangetypes?

From: Andreas Joseph Krogh <andreak(at)officenet(dot)no>
To: Postgres General <pgsql-general(at)postgresql(dot)org>
Subject: Why is NULL = unbounded for rangetypes?
Date: 2013-07-08 08:19:18
Message-ID: OrigoEmail.b39.9039764ca71b5d10.13fbd566210@prod2
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

<div>Hi.</div>

<div> </div>

<div>Both of these queries return TRUE because NULL means &quot;unmounded&quot;:</div>

<div>
<style type="text/css"></style>
<pre class="western" style="text-align: left">
<font face="DejaVu Sans Mono"><font color="#000080"><b>select daterange</b></font><font color="#000000">(</font><font color="#008000"><b>'2013-07-01' </b></font><font color="#000000">:: </font><font color="#000080"><b>DATE</b></font><font color="#000000">, </font><font color="#000080"><b>null</b></font><font color="#000000">, </font><font color="#008000"><b>'[]'</b></font><font color="#000000">) &amp;&amp; </font><font color="#000080"><b>daterange</b></font><font color="#000000">(</font><font color="#008000"><b>'2013-07-04' </b></font><font color="#000000">:: </font><font color="#000080"><b>DATE</b></font><font color="#000000">, </font><font color="#008000"><b>'2013-07-30' </b></font><font color="#000000">:: </font><font color="#000080"><b>DATE</b></font><font color="#000000">, </font><font color="#008000"><b>'[]'</b></font><font color="#000000">);</font></font>
<font face="DejaVu Sans Mono"><font color="#000080"><b>select daterange</b></font><font color="#000000">(</font><font color="#000080"><b>null</b></font><font color="#000000">, </font><font color="#008000"><b>'2013-08-11' </b></font><font color="#000000">:: </font><font color="#000080"><b>DATE</b></font><font color="#000000">, </font><font color="#008000"><b>'[]'</b></font><font color="#000000">) &amp;&amp; </font><font color="#000080"><b>daterange</b></font><font color="#000000">(</font><font color="#008000"><b>'2013-07-04' </b></font><font color="#000000">:: </font><font color="#000080"><b>DATE</b></font><font color="#000000">, </font><font color="#008000"><b>'2013-07-30' </b></font><font color="#000000">:: </font><font color="#000080"><b>DATE</b></font><font color="#000000">, </font><font color="#008000"><b>'[]'</b></font><font color="#000000">);</font></font></pre>

<div>What is the rational behind this behavior of NULL?</div>
</div>

<div> 
<div class="origo-email-signature">--<br>
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>
Public key: http://home.officenet.no/~andreak/public_key.asc</div>
</div>

Attachment Content-Type Size
unknown_filename text/html 2.3 KB

Responses

Browse pgsql-general by date

  From Date Subject
Next Message Jov 2013-07-08 09:31:19 backend hangs at sendto() and can't be terminated
Previous Message Kevin Grittner 2013-07-08 07:42:57 Re: Efficiency of materialized views refresh in 9.3