"FETCH returns data as if it were a SELECT result"

Lists: pgsql-docs
From: Roman Neuhauser <neuhauser(at)sigpipe(dot)cz>
To: pgsql-docs(at)postgresql(dot)org
Subject: "FETCH returns data as if it were a SELECT result"
Date: 2005-08-02 15:32:48
Message-ID: 20050802153248.GA5320@isis.sigpipe.cz
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"The variant of FETCH described here returns the data as if it were a
SELECT result rather than placing it in host variables."

http://www.postgresql.org/docs/current/static/sql-fetch.html

That doesn't seem to be the case. Try the following script:

CREATE TABLE t1 (t1i INT, t1c CHAR(1));
CREATE TABLE t2 (t2i INT, t2c CHAR(1));

INSERT INTO t1 VALUES (1, 'a');
INSERT INTO t1 VALUES (2, 'b');
INSERT INTO t1 VALUES (3, 'c');

BEGIN;
INSERT INTO t2 (SELECT * FROM t1);
SELECT * FROM t2;
ROLLBACK;

BEGIN;
DECLARE c1 CURSOR FOR SELECT * FROM t1;
INSERT INTO t2 (FETCH ALL FROM c1);
ROLLBACK;

The output I get:

CREATE TABLE
CREATE TABLE
INSERT 19110 1
INSERT 19111 1
INSERT 19112 1
BEGIN
INSERT 0 3
t2i | t2c
-----+-----
1 | a
2 | b
3 | c
(3 rows)

ROLLBACK
BEGIN
DECLARE CURSOR
psql:tmp/fetch-is-unlike-select.sql:15: ERROR: syntax error at or near "ALL" at character 23
psql:tmp/fetch-is-unlike-select.sql:15: LINE 1: INSERT INTO t2 (FETCH ALL FROM c1);
psql:tmp/fetch-is-unlike-select.sql:15: ^
ROLLBACK

This is on PostgreSQL 8.0.3 on i386-portbld-freebsd4.11, compiled by GCC 2.95.4

--
How many Vietnam vets does it take to screw in a light bulb?
You don't know, man. You don't KNOW.
Cause you weren't THERE. http://bash.org/?255991


From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Roman Neuhauser <neuhauser(at)sigpipe(dot)cz>
Cc: pgsql-docs(at)postgresql(dot)org
Subject: Re: "FETCH returns data as if it were a SELECT result"
Date: 2005-08-02 17:09:58
Message-ID: 11939.1123002598@sss.pgh.pa.us
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Lists: pgsql-docs

Roman Neuhauser <neuhauser(at)sigpipe(dot)cz> writes:
> "The variant of FETCH described here returns the data as if it were a
> SELECT result rather than placing it in host variables."

> That doesn't seem to be the case.

It means it returns data *to the client* in the same way a SELECT does.

regards, tom lane


From: Roman Neuhauser <neuhauser(at)sigpipe(dot)cz>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-docs(at)postgresql(dot)org
Subject: Re: "FETCH returns data as if it were a SELECT result"
Date: 2005-08-02 19:04:29
Message-ID: 20050802190429.GA7082@isis.sigpipe.cz
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# tgl(at)sss(dot)pgh(dot)pa(dot)us / 2005-08-02 13:09:58 -0400:
> Roman Neuhauser <neuhauser(at)sigpipe(dot)cz> writes:
> > "The variant of FETCH described here returns the data as if it were a
> > SELECT result rather than placing it in host variables."
>
> > That doesn't seem to be the case.
>
> It means it returns data *to the client* in the same way a SELECT does.

Ok, and what does *that* mean? If you spend a few minutes on an
explanation, I'll submit a patch to the documentation.

--
How many Vietnam vets does it take to screw in a light bulb?
You don't know, man. You don't KNOW.
Cause you weren't THERE. http://bash.org/?255991