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Re: Left and Right Joins

From: Alan D. Mills <alanmNOSPAM_at_uk.europe.mcd.mot.com>
Date: Tue, 8 Sep 1998 11:30:08 +0100
Message-ID: <6t30uc$7nn$1@schbbs.mot.com>


Excuse my ignorance on this but what are the definitions of the terms Left Join and Right Join. My experience of Oracle I know Inner joins and Outer joins but I've not encountered the terms left and right join before.

As I see it, the two examplke below for left and right join are exactly the same (to all intents and purposes) so why differentiate between them by giving them different names?

I presume I'm missing something here. Can anybody fill me in?

--
Alan D. Mills

Arjan van Bentem wrote in message <6t135f$kid$1_at_newton.a2000.nl>...
>Suppose your table Addresses has a person's name as the primary key, but
>might not have an address for each person.
>
>Left join:
>
> select a.name, b.address
> from persons a
> , addresses b
> where b.name (+) = a.name;
>
>Right join:
>
> where a.name = b.name (+);
>
>Innerjoin:
>
> where a.name = b.name;
>
>Arjan.
>
>
Received on Tue Sep 08 1998 - 05:30:08 CDT

Original text of this message

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