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Date: Thu, 8 Jun 2006 23:47:16 -0500
From: "Aaron Bono" <postgresql@aranya.com>
To: pgsql-sql@postgresql.org
Subject: Re: empty set
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That will work if foo is never NULL.  If foo takes on a NULL value you will
get those records where it is NULL.

Is there a reason you cannot do an if/else statement on the list size?  That
is what I do on my queries.

-Aaron

On 6/8/06, Scott Marlowe <smarlowe@g2switchworks.com> wrote:
>
> On Thu, 2006-06-08 at 16:40, CG wrote:
> > PostgreSQL 8.1
> >
> > I've been trying to write a SQL prepare routine. One of the challenging
> > elements I'm running into is an empty set ...
> >
> > "select foo from bar where foo in ? ;"
> >
> > What if "?" is an set with zero elements? What is the proper value to
> use to
> > replace "?" indicating an empty set?
>
> NULL?
>
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> TIP 5: don't forget to increase your free space map settings
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That will work if foo is never NULL.&nbsp; If foo takes on a NULL value you will get those records where it is NULL.<br><br>Is there a reason you cannot do an if/else statement on the list size?&nbsp; That is what I do on my queries.
<br><br>-Aaron<br><br><div><span class="gmail_quote">On 6/8/06, <b class="gmail_sendername">Scott Marlowe</b> &lt;<a href="mailto:smarlowe@g2switchworks.com">smarlowe@g2switchworks.com</a>&gt; wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
On Thu, 2006-06-08 at 16:40, CG wrote:<br>&gt; PostgreSQL 8.1<br>&gt;<br>&gt; I've been trying to write a SQL prepare routine. One of the challenging<br>&gt; elements I'm running into is an empty set ...<br>&gt;<br>&gt; &quot;select foo from bar where foo in ? ;&quot;
<br>&gt;<br>&gt; What if &quot;?&quot; is an set with zero elements? What is the proper value to use to<br>&gt; replace &quot;?&quot; indicating an empty set?<br><br>NULL?<br><br>---------------------------(end of broadcast)---------------------------
<br>TIP 5: don't forget to increase your free space map settings<br></blockquote></div><br><br>

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