Re: Proposal for supporting outer joins in 7.1

Поиск
Список
Период
Сортировка
От Philip Warner
Тема Re: Proposal for supporting outer joins in 7.1
Дата
Msg-id 3.0.5.32.20000827195657.02ac8100@mail.rhyme.com.au
обсуждение исходный текст
Ответ на Proposal for supporting outer joins in 7.1  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: Proposal for supporting outer joins in 7.1  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-hackers
At 16:07 25/08/00 -0400, Tom Lane wrote:
> For example:
>
>SELECT ... FROM a,b,c
>    Planner will consider all three possible join orders:
>    (a cross join b) cross join c
>    (a cross join c) cross join b
>    (b cross join c) cross join a
>
>SELECT ... FROM (a cross join b) cross join c
>    Planner will only consider joining a with b and then adding c.
>

I'm not sure whether the above is the syntax you plan to use, but it looks
a little too much like:

SELECT ... FROM (select * from a cross join b) as z cross join c

which has a quite different meaning to any kind of outer join, and the
parenthesis, in this case, should not affect the planner choices. I don;t
think that support for this kind of query is implemented, but it could
confuse things a little.

As an aside, while you are in there, I don't suppose you would be able to
implement that above syntax as well? Then, maybe, have a go at the common
cold, too.


----------------------------------------------------------------
Philip Warner                    |     __---_____
Albatross Consulting Pty. Ltd.   |----/       -  \
(A.B.N. 75 008 659 498)          |          /(@)   ______---_
Tel: (+61) 0500 83 82 81         |                 _________  \
Fax: (+61) 0500 83 82 82         |                 ___________ |
Http://www.rhyme.com.au          |                /           \|                                |    --________--
PGP key available upon request,  |  /
and from pgp5.ai.mit.edu:11371   |/


В списке pgsql-hackers по дате отправления:

Предыдущее
От: Oleg Bartunov
Дата:
Сообщение: current cvs is broken with --enable-multibyte
Следующее
От: Magnus Hagander
Дата:
Сообщение: RE: Access PostgreSQL server via SSL/Internet