SELECT or INSERT a row in one command

Question

I\'m using PostgreSQL 9.0 and I have a table with just an artificial key (auto-incrementing sequence) and another unique key. (Yes, there is a reason for this table. :)) I w

Answer 1

Have you tried to union it?

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Edit - this requires Postgres 9.1:

create table mytable (id serial primary key, other_key varchar not null unique);

WITH new_row AS (
INSERT INTO mytable (other_key)
SELECT 'SOMETHING'
WHERE NOT EXISTS (SELECT * FROM mytable WHERE other_key = 'SOMETHING')
RETURNING *
)
SELECT * FROM new_row
UNION
SELECT * FROM mytable WHERE other_key = 'SOMETHING';

results in:

 id | other_key 
----+-----------
  1 | SOMETHING
(1 row)