On Tue, Jun 30, 2009 at 9:58 AM, Waldemar
Bergstreiser<littlesuspense@web.de> wrote:
>> > -- c *= b *= a =* d =* f
>> > select * from a, outer( b, outer c), outer (d, outer f )
>> > where a.b_id = b.id and b.c_id = c.id and a.d_id = d.id and d.f_id = f.id;
>>
>> from a full join b on (a.id=b.id)
>> full join c on (b.id=c.id)
>> full join d
>>
>
> I guess, you don't get it. Probably so
I don't get it either. by *= do you mean the Oracle-style outer join?
in which case why is this not just
select * from a,
left outer join b on (a.b_id = b.id)
left outer join c on (b.c_id = c.id)
left outer join d on (a.d_id = d.id)
left outer join f on (d.f_id = f.id)
You can parenthesize it different ways but I think the result in this
case is actually the same.
> select * from a left outer join b on (a.b_id=b.id) ....
>
> But I don't see any clear way to specify that table C should be outer joined only if we got a row from table B.
Well that would be the default since if you get no row from b b.c_id
will be null.
--
greg
http://mit.edu/~gsstark/resume.pdf
