Re: Proposal for supporting outer joins in 7.1

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От Philip Warner
Тема Re: Proposal for supporting outer joins in 7.1
Дата
Msg-id 3.0.5.32.20000828033825.02ab0690@mail.rhyme.com.au
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Ответ на Re: Proposal for supporting outer joins in 7.1  (Tom Lane <tgl@sss.pgh.pa.us>)
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At 11:38 27/08/00 -0400, Tom Lane wrote:
>Philip Warner <pjw@rhyme.com.au> writes:
>>> SELECT ... FROM (a cross join b) cross join 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,
>
>Huh?  AFAIK they mean exactly the same thing, modulo a few issues about
>visibility of columns.  In any case you'll have to take your complaint
>to ISO, because that's what the spec says the syntaxes are.

Sorry, I should have written:
   SELECT ... FROM (select * from a,b) as z, c

which does not do an outer join, and does not imply any ordering.


>> I don;t think that support for this kind of query is implemented,
>
>Not yet, but it's certainly on the TODO list.  I'm not seriously
>thinking about getting subselect-in-FROM done in this go-round,
>though.

Great! If by Subselect-in-from you mean something like what I wrote above,
then it is a major win.


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