Thread: INSERT INTO...RETURNING vs SELECT

I was doing some experimenting and was wondering why the following does
not work:

CREATE TABLE accounts ( id SERIAL PRIMARY KEY NOT NULL, accounts_id INTEGER REFERENCES accounts, name TEXT
);

INSERT INTO accounts (accounts_id, name) VALUES ( (INSERT INTO accounts (accounts_id, name) VALUES (NULL, 'test 1')
RETURNINGid), 'test 2');
 

ERROR:  syntax error at or near "INTO"

Of course, the following works fine:

INSERT INTO accounts (accounts_id, name) VALUES (NULL, 'test 1');
INSERT INTO accounts (accounts_id, name) VALUES ( (SELECT id FROM accounts WHERE name='test 1'), 'test 2');


As far as I can see, INSERT INTO...RETURNING is semantically equivalent
to SELECT...FROM with a side-effect, so it seems this construct should
work.  Can someone shed some light?

Regards,
Cliff

Cliff Wells <cliff@develix.com> wrote:

> As far as I can see, INSERT INTO...RETURNING is semantically equivalent
> to SELECT...FROM with a side-effect, so it seems this construct should
> work.  Can someone shed some light?

Well, at the moment you can't reuse the RETURNING-values, you have to
wait for 9.1, writeable CTE.


Andreas
-- 
Really, I'm not out to destroy Microsoft. That will just be a completely
unintentional side effect.                              (Linus Torvalds)
"If I was god, I would recompile penguin with --enable-fly."   (unknown)
Kaufbach, Saxony, Germany, Europe.              N 51.05082°, E 13.56889°

On Mon, 2010-04-05 at 09:10 +0200, Andreas Kretschmer wrote:
> Cliff Wells <cliff@develix.com> wrote:
> 
> > As far as I can see, INSERT INTO...RETURNING is semantically equivalent
> > to SELECT...FROM with a side-effect, so it seems this construct should
> > work.  Can someone shed some light?
> 
> Well, at the moment you can't reuse the RETURNING-values, you have to
> wait for 9.1, writeable CTE.

Thanks, I just wanted to make sure I wasn't misunderstanding something.

Regards,
Cliff