Re: Proposal for supporting outer joins in 7.1
От | Philip Warner |
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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
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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 |/
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