From: Ragnar <gnari@hive.is>
To: emilu@encs.concordia.ca
Cc: pgsql-sql@postgresql.org
Subject: Re: Is it possible to left join based on previous joins
Date: Thu, 07 Sep 2006 14:30:50 +0000
Message-ID: <1157639450.17224.73.camel@localhost.localdomain> (raw)
In-Reply-To: <45002689.9050307@encs.concordia.ca>
References: <45001AF6.4020706@encs.concordia.ca>
<45002689.9050307@encs.concordia.ca>
On fim, 2006-09-07 at 10:02 -0400, Emi Lu wrote:
> I tried the example as the following:
>
> create table a(col1);
> create table b(col1, col2)
>
> select a.*
> from a inner join b using(col2)
> left join b.col2 as c on (c.col1 = a.col1)
>
> System notifies me that b is not a schema name.
>
> So, I guess the approach that I tried to do is not acceptable by Pgsql
> grammar.
it seems to me that basically you want to
select from a table whose name is stored in another
table.
one way to do that would be to use plpgsql or
some other procedural language to create
a set returning function, so that you
could do:
SELECT * from selfromtab('sometable');
after that is done,you might be able to use that
in joins
gnari
>
>
> >
> > Is it possible to do something like:
> >
> > select ...
> > from t1
> > inner join t2 ...
> > left join t2.colN
> >
> > When t1 inner join with t2 I got unique result for t2.colN( colN's value
> > is table name).
> >
> > Can I continue to left join with the column "colN" in table t2?
> >
> > Thanks
> >
> >
> >
> >
> > ---------------------------(end of broadcast)---------------------------
> > TIP 4: Have you searched our list archives?
> >
> > http://archives.postgresql.org
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 2: Don't 'kill -9' the postmaster
>
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To: pgsql-sql@postgresql.org
Cc: gnari@hive.is, emilu@encs.concordia.ca
Subject: Re: Is it possible to left join based on previous joins
In-Reply-To: <1157639450.17224.73.camel@localhost.localdomain>
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