Re: Problem using Subselect results
От | oheinz@stud.fbi.fh-darmstadt.de |
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Тема | Re: Problem using Subselect results |
Дата | |
Msg-id | 1059051709.3f1fd8bd630bc@stud.fbi.fh-darmstadt.de обсуждение исходный текст |
Ответ на | Re: Problem using Subselect results (Christoph Haller <ch@rodos.fzk.de>) |
Ответы |
Re: Problem using Subselect results
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Список | pgsql-sql |
SELECT my_c.b, my_c.c FROM (SELECT table2.b, table2.c FROM table2, (SELECT table1.a, table1.b FROM table1 WHERE (table1.b = 1)) my_ab WHERE (table2.a = my_ab.a)) my_c; You were doing what I wanted to avoid - you are using a "SUBSUBSELECT". But (now) I believe it's not possible to refer to a subselect's resultset on the same level of hierarchy - which sounds rather meaningful - because you couldn't tell which of them was being processsed first. So I'll have to get my SELECT statement into some kind of hierarchy, which makes things a bit more complicated (with twentysomething SELECT statements) Thanks, Oliver Quoting Christoph Haller <ch@rodos.fzk.de>: > Does this match your intentions: > CREATE VIEW my_view AS SELECT b,c FROM > (SELECT b,c FROM table2, (SELECT a, b FROM table1 WHERE b=3D1) my_ab > WHERE table3.a=3Dmy_ab.a) my_c; > I assume the reference table3.a is a typo. > > Regards, Christoph > > > I want to use the result of a subselect as condition in another one. > > > > table1: a,b > > table2: a,c > > > > CREATE VIEW my_view AS SELECT b,c > > (SELECT a, b FROM table1 WHERE b=3D1) my_ab, > > (SELECT c FROM table2, my_ab WHERE table3.a=3Dmy_ab.a) my_c; > > > > this is just an example - i know i could cross join this one, but i > need = > > to=20 > > refer to the results of several subselects in several other. > > > > > > does return "relation my_ab unknown". it is not just a problem of > executi= > > on=20 > > order - if i turn it the other way round it's still the same. > > > > Am I just trying to do something really stupid? And what for is the > (nece= > > ssary)=20 > > AS statement for subselects, if it's not possible to access their > results= > > by=20 > > that name? > > > > And as I need the result of a subselect in several other subselects > it's= > > not=20 > > possible to transform them into a cascade of sub, subsub, > subsubsub.... s= > > elects. > > Any ideas?=20 > > ------------------------------------------------- This mail sent through IMP: http://horde.org/imp/
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