From: Tomasz Myrta <jasiek@klaster.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-sql@postgresql.org
Subject: Re: order by and aggregate
Date: Mon, 06 Jan 2003 18:07:57 +0100
Message-ID: <3E19B7ED.4020901@klaster.net> (raw)
In-Reply-To: <3E197A39.8070808@klaster.net>
References: <3E197A39.8070808@klaster.net>
<14734.1041870875@sss.pgh.pa.us>
Tom Lane wrote:
> I don't understand what you think is wrong with this solution. It works
> fine for me:
>
> regression=# create view vv as
> regression-# select max(unique1) from (select unique1 from tenk1
> regression(# order by unique2) x;
> CREATE VIEW
> regression=# explain select * from vv;
> QUERY PLAN
>
> ---------------------------------------------------------------------------------------------------
> Subquery Scan vv (cost=523.00..523.00 rows=1 width=8)
> -> Aggregate (cost=523.00..523.00 rows=1 width=8)
> -> Subquery Scan x (cost=0.00..498.00 rows=10000 width=8)
> -> Index Scan using tenk1_unique2 on tenk1
> (cost=0.00..498.00 rows=10000 width=8)
> (4 rows)
>
OK, your view is ok.
I think, you don't remember my questions about "joining views" and
"sub-select with aggregate" dated on 2002-10-23, so I qoute your answer
on that question (joining views):
>I think this is the same issue that Stephan identified in his response
>to your other posting ("sub-select with aggregate"). When you write
> FROM x join y using (col) WHERE x.col = const
>the WHERE-restriction is only applied to x. I'm afraid you'll need
>to write
> FROM x join y using (col) WHERE x.col = const AND y.col = const
>Ideally you should be able to write just
> FROM x join y using (col) WHERE col = const
>but I think that will be taken the same as "x.col = const" :-(
I have the same problem here, query is a bit complicated and has
some_table join (subselect) X using (some_field) which doesn't work.
Regards,
Tomasz Myrta
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To: pgsql-sql@postgresql.org
Cc: jasiek@klaster.net, tgl@sss.pgh.pa.us
Subject: Re: order by and aggregate
In-Reply-To: <3E19B7ED.4020901@klaster.net>
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