From: Abhinandan Raghavan <Abhinandan.Raghavan@unige.ch>
To: pgsql-sql@postgresql.org
Subject: Self-Join
Date: Tue, 06 Dec 2011 14:57:19 +0100
Message-ID: <4EDE1F3F.6060807@unige.ch> (raw)
Hi,
I'm looking to frame an SQL statement in Postgres for what's explained
in the attached image.
The original table is at the top and is called NAV (Short for Name,
Attribute, Value). I want to create a view (NWHA_View) involving values
from within (presumably from a self join). I would've normally created a
view in the following way:
SELECTA.NAME <http://a.name/;,
A.VALUE AS WEIGHT,
B.VALUE AS HEIGHT,
C.VALUE AS AGE
FROM NAV A,
NAV B,
NAV C
WHEREA.NAME <http://a.name/>=B.NAME <http://b.name/;
ANDA.NAME <http://a.name/>=C.NAME <http://c.name/;
AND A.ATTRIBUTE = 'Weight'
AND B.ATTRIBUTE = 'Height'
AND C.ATTRIBUTE = 'Age'
The only problem when I create a view with the above select statement is
that when there are no entries for the field name "AGE" (in the case of
David), then the row does not get displayed. What's the way out in
Postgresql? I know the way it is addressed in Oracle but it doesn't seem
to work in Postgresql.
Thanks.
Abhi
Attachments:
[image/png] selfjoin_example.png (16.2K, ../4EDE1F3F.6060807@unige.ch/3-selfjoin_example.png)
download | view image
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To: pgsql-sql@postgresql.org
Cc: Abhinandan.Raghavan@unige.ch
Subject: Re: Self-Join
In-Reply-To: <4EDE1F3F.6060807@unige.ch>
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