From: Ray Madigan <ray@madigans.org>
To: Pgsql-Sql <pgsql-sql@postgresql.org>
Subject: Re: LinkedList
Date: Wed, 26 Apr 2006 10:35:15 -0700
Message-ID: <IEELLOAPJFACBDBGELGHAELAEDAA.ray@madigans.org> (raw)
In-Reply-To: <1146067158.23538.264.camel@state.g2switchworks.com>
Scott,
Thanks for your reply, I tried what you said, worked around a few things
but I am still stuck. The main reason is I didn't do an adequate job of
explaining the situation. The table implements many linked lists and I want
to traverse one of them given the end of the list.
Say the table contains
h | v | j
1 0 100
3 1 300
5 3 500
7 5 700
2 0 200
4 2 400
6 4 600
8 6 800
If I specify t.h = 8 I want to traverse the even part of the table
If I specify t.h = 7 I want to traverse the odd part of the table
If you can send me to a book to read I am willing
Thanks
-----Original Message-----
From: pgsql-sql-owner@postgresql.org
[mailto:pgsql-sql-owner@postgresql.org]On Behalf Of Scott Marlowe
Sent: Wednesday, April 26, 2006 8:59 AM
To: Ray Madigan
Cc: pgsql-sql@postgresql.org
Subject: Re: [SQL] LinkedList
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.
---------------------------(end of broadcast)---------------------------
TIP 2: Don't 'kill -9' the postmaster
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-sql@postgresql.org
Cc: ray@madigans.org
Subject: Re: LinkedList
In-Reply-To: <IEELLOAPJFACBDBGELGHAELAEDAA.ray@madigans.org>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox