Re: order by and aggregate

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-restrictionis only applied to x.  I'm afraid you'll need>to write>    FROM x join y using (col) WHERE x.col =
constAND y.col = const>Ideally you should be able to write just>    FROM x join y using (col) WHERE col = const>but I
thinkthat 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