Re: Basic SQL join question - Mailing list pgsql-general

From Michael Meskes
Subject Re: Basic SQL join question
Date
Msg-id 20030131070011.GE8090@feivel.fam-meskes.de
Whole thread Raw
In response to Basic SQL join question  (Jean-Christian Imbeault <jc@mega-bucks.co.jp>)
Responses Re: Basic SQL join question
List pgsql-general
On Fri, Jan 31, 2003 at 12:08:24PM +0900, Jean-Christian Imbeault wrote:
> For example
> ...
> What is the proper SQL to return:
>
>   a |  b |  c
> ---------------
>  a1   b1   c1
>  a2   b2   c2
>  a3        c3
>            c4

None. Even in theory this is not possible. How shall the database system
know that a1,b1,c1 belong together? You said the tables have absolutely
nothing in common. Keep in mind that SQL works on sets, not on single
values.

Michael
--
Michael Meskes
Email: Michael@Fam-Meskes.De
ICQ: 179140304
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