Use "union" ???
-----Original Message-----
From: pgsql-general-owner@postgresql.org
[mailto:pgsql-general-owner@postgresql.org] On Behalf Of Stefan
Schwarzer
Sent: Wednesday, October 24, 2007 9:09 AM
To: pgsql-general@postgresql.org
Subject: [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
