Subject: Re: LinkedList
From: Scott Marlowe <smarlowe@g2switchworks.com>
To: Ray Madigan <ray@madigans.org>
Cc: pgsql-sql@postgresql.org
In-Reply-To: <IEELLOAPJFACBDBGELGHIEKMEDAA.ray@madigans.org>
References: <IEELLOAPJFACBDBGELGHIEKMEDAA.ray@madigans.org>
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Message-Id: <1146067158.23538.264.camel@state.g2switchworks.com>
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Date: Wed, 26 Apr 2006 10:59:18 -0500

On Wed, 2006-04-26 at 11:09, Ray Madigan wrote:
> I have a table that I created that implements a linked list.  I am not an
> expert SQL developer and was wondering if there are known ways to traverse
> the linked lists.  Any information that can point me in the direction to
> figure this out would be appreciated.  The table contains many linked lists
> based upon the head of the list and I need to extract all of the nodes that
> make up a list.  The lists are simple with a item and a link to the history
> item so it goes kind of like:
> 
> 1, 0
> 3, 1
> 7, 3
> 9, 7
> ...
> 
> Any suggestions would be helpful, or I will have to implement the table
> differently.

You should be able to do this with a fairly simple self-join...

select a.id, b.aid, a.field1, b.field1 
from mytable a
join mytable b
on (a.id=b.aid)

Or something like that.