From: | "Stanislav Raskin" <sr(at)brainswell(dot)de> |
---|---|
To: | "'Stefan Schwarzer'" <stefan(dot)schwarzer(at)grid(dot)unep(dot)ch>, <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: "Concatenate" two queries - how? |
Date: | 2007-10-24 13:27:23 |
Message-ID: | E1IkgGe-0007KZ-00@teena.zerebecki.de |
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Thread: | |
Lists: | pgsql-general |
I don't know whether I did understand you entirely, but you might want to
take a look at the UNION clause:
http://www.postgresql.org/docs/8.2/interactive/sql-select.html#SQL-UNION
-----Ursprüngliche Nachricht-----
Von: pgsql-general-owner(at)postgresql(dot)org
[mailto:pgsql-general-owner(at)postgresql(dot)org] Im Auftrag von Stefan Schwarzer
Gesendet: Mittwoch, 24. Oktober 2007 15:09
An: pgsql-general(at)postgresql(dot)org
Betreff: [GENERAL] "Concatenate" two queries - how?
Hi there,
I have two queries, which I would like to bring together to form one
result.
The first query is a simple SELECT on a table of national statistics.
SELECT
COALESCE(c.name, ''''),
year_start AS year,
value
FROM
fish_catch AS d
LEFT JOIN
countries AS c ON c.id = id_country
WHERE
(year_start = 1995 OR year_start = 2000 ) AND
(name = 'Afghanistan' OR name = 'Albania' )
The second query is an aggregation-on-the-fly of these national
statistics to its regions. The result is for example not "Germany,
France, Algeria, ...", but "Europe, Africa, ..."
SELECT
COALESCE(r.name, ''''),
year_start AS year,
SUM(value) AS value
FROM
life_expect AS d
LEFT JOIN
countries_view AS c ON c.id = id_country
RIGHT JOIN
regions AS r ON r.id = c.reg_id
WHERE
(year_start = 1995 OR year_start = 2000 ) AND
(r.name = 'Europe')
GROUP BY
r.name, year_start
Now, I want to enable queries which display national as well as
regional values. I could probably work with independent queries, but
I think it would be "cleaner" and more efficient to get everything
into a single query.
Can someone give me a hint how this would work?
Thanks a lot!
Stef
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
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