Re: Outer join in postgresql

On Mon, 12 Jun 2000, Patrick Kay wrote:
> I am looking for a way run an outer join in psql. Can anyone help?
>
> Informix has an "OUTER" keyword. I don't see anything like this in the docs
> for psql.
>
> Thanks much.
> -Pat Kay

Here is an example I have about simulating an outer join in PostgreSQL:
(hope this is correct, I'm still a bit of a novice but getting better)

CREATE TABLE master (m_id INTEGER, m_name TEXT);
CREATE TABLE slave (m_id INTEGER, s_name TEXT);

INSERT INTO master (m_id, m_name) VALUES (1, 'Satan');
INSERT INTO master (m_id, m_name) VALUES (2, 'God');

INSERT INTO slave (m_id, s_name) VALUES (1, 'Joe');
INSERT INTO slave (m_id, s_name) VALUES (1, 'Tom');

SELECT * FROM master m, slave s
WHERE m.m_id = s.m_id
UNION
SELECT *, NULL, 'no slaves'
FROM master m
WHERE m.m_id NOT IN ( SELECT m_id FROM slave );

m_id | m_name | m_id | s_name
------+--------+------+-----------
1 | Satan | 1 | Joe
1 | Satan | 1 | Tom
2 | God | | no slaves
(3 rows)

-- Oracle outer-join
SELECT * FROM master m, slave s
WHERE m.m_id = s.m_id (+);

m_id | m_name | m_id | s_name
------+--------+------+-----------
1 | Satan | 1 | Joe
1 | Satan | 1 | Tom
2 | God | |
(3 rows)

I keep a file at http://comptechnews.com/~reaster/dbdesign.html that has
some info that might be useful to some people.

--
Robert B. Easter