Re: Self-Join

Hi Abhinandan,

it's just the same outer join you'd do in Oracle, see:

http://www.postgresql.org/docs/9.1/static/tutorial-join.html

Bèrto

On 6 December 2011 16:57, Abhinandan Raghavan
<Abhinandan(dot)Raghavan(at)unige(dot)ch>wrote:

> 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:
>
>
> SELECT A.NAME <http://a.name/>,
> A.VALUE AS WEIGHT,
> B.VALUE AS HEIGHT,
> C.VALUE AS AGE
>
> FROM NAV A,
> NAV B,
> NAV C
>
> WHERE A.NAME <http://a.name/> = B.NAME <http://b.name/>
> AND A.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
>
>
>
>
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