Returning multiple values (but one row) in plpgsql

Karl O. Pinc wrote:

I want to return multiple values, but not a set, only a single row,
from a
plpgsql function and I can't seem to get it to work. (I suppose I'd be
happy to return a set, but I can't seem to make that work either.
Anyway,
what's wrong with this?)

Version is:

$ rpm -q postgresql
postgresql-7.3.4-3.rhl9
$ cat /etc/redhat-release Red Hat Linux release 9 (Shrike)

Code is:

-- Tests for returning multiple values

CREATE TYPE returntype AS (a INT, b INT);

CREATE FUNCTION return_multiple()
RETURNS returntype
LANGUAGE plpgsql
AS '

DECLARE
myvar returntype;

BEGIN
myvar.a := 1;
myvar.b := 2;

RETURN myvar;
END;
';

SELECT return_multiple();

DROP FUNCTION return_multiple();
DROP TYPE returntype CASCADE;

Errors are:

WARNING: plpgsql: ERROR during compile of return_multiple near line 9
ERROR: return type mismatch in function returning tuple at or near
"myvar"

Thanks.

Karl <kop@meme.com>
Free Software: "You don't pay back, you pay forward."
-- Robert A. Heinlein

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It works with 7.4.3, except the SELECT statement is
testdb=# SELECT * FROM return_multiple();
a | b
---+---
1 | 2
(1 row)

Ron

Hmmm,

Isn't it just easier to make a function which does that and add the
functions to the SELECT portion of statement instead of adding it to
the FROM clause?

as in:
Select invnum, YourFunction(invdet, total), YourFunction(invdet, othertotal)
FROM yourtable

Regards,

Arthur

On 2004.09.08 14:25 Arthur Hoogervorst wrote:

Hmmm,

Isn't it just easier to make a function which does that and add the
functions to the SELECT portion of statement instead of adding it to
the FROM clause?

as in:
Select invnum, YourFunction(invdet, total), YourFunction(invdet,
othertotal)
FROM yourtable

My function is both computationaly intensive and has side effects,
necessitating a single function call.

Regards,

Arthur

On Wed, 8 Sep 2004 13:51:33 -0500, Karl O. Pinc <kop@meme.com> wrote:

I want to return multiple values, but not a set, only a single row,
from a
plpgsql function and I can't seem to get it to work. (I suppose I'd

be

happy to return a set, but I can't seem to make that work either.
Anyway,
what's wrong with this?)

Version is:

$ rpm -q postgresql
postgresql-7.3.4-3.rhl9
$ cat /etc/redhat-release Red Hat Linux release 9 (Shrike)

Code is:

-- Tests for returning multiple values

CREATE TYPE returntype AS (a INT, b INT);

CREATE FUNCTION return_multiple()
RETURNS returntype
LANGUAGE plpgsql
AS '

DECLARE
myvar returntype;

BEGIN
myvar.a := 1;
myvar.b := 2;

RETURN myvar;
END;
';

SELECT return_multiple();

DROP FUNCTION return_multiple();
DROP TYPE returntype CASCADE;

Errors are:

WARNING: plpgsql: ERROR during compile of return_multiple near line

9

ERROR: return type mismatch in function returning tuple at or near
"myvar"

Thanks.

Karl <kop@meme.com>
Free Software: "You don't pay back, you pay forward."
-- Robert A. Heinlein

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Karl <kop@meme.com>
Free Software: "You don't pay back, you pay forward."
-- Robert A. Heinlein

Poo. Looks like my postgresql has a bug. :-(

The only work-around I can think of is to return
a bunch of values in a delimited string and then
parse them out upon return. :-(

Anybody got a better idea? Anybody know just when
this was fixed? If I knew I might be able to see about
getting our site upgraded. (I tried looking in the CVS
web interface, but was quickly daunted by the number of
source files.)

On 2004.09.08 14:07 Ron St-Pierre wrote:

Karl O. Pinc wrote:

I want to return multiple values, but not a set, only a single row,
from a
plpgsql function and I can't seem to get it to work. (I suppose I'd
be
happy to return a set, but I can't seem to make that work either.
Anyway,
what's wrong with this?)

Version is:

$ rpm -q postgresql
postgresql-7.3.4-3.rhl9
$ cat /etc/redhat-release Red Hat Linux release 9 (Shrike)

Code is:

-- Tests for returning multiple values

CREATE TYPE returntype AS (a INT, b INT);

CREATE FUNCTION return_multiple()
RETURNS returntype
LANGUAGE plpgsql
AS '

DECLARE
myvar returntype;

BEGIN
myvar.a := 1;
myvar.b := 2;

RETURN myvar;
END;
';

SELECT return_multiple();

DROP FUNCTION return_multiple();
DROP TYPE returntype CASCADE;

Errors are:

WARNING: plpgsql: ERROR during compile of return_multiple near line
9
ERROR: return type mismatch in function returning tuple at or near
"myvar"

Thanks.

Karl <kop@meme.com>
Free Software: "You don't pay back, you pay forward."
-- Robert A. Heinlein

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It works with 7.4.3, except the SELECT statement is
testdb=# SELECT * FROM return_multiple();
a | b
---+---
1 | 2
(1 row)

Ron

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Karl <kop@meme.com>
Free Software: "You don't pay back, you pay forward."
-- Robert A. Heinlein

Karl O. Pinc wrote:

Anybody got a better idea? Anybody know just when
this was fixed? If I knew I might be able to see about
getting our site upgraded. (I tried looking in the CVS
web interface, but was quickly daunted by the number of
source files.)

select version();
version
-------------------------------------------------------------------------
PostgreSQL 7.3.7 on x86_64-unknown-linux-gnu, compiled by GCC gcc
(GCC) 3.3.3 20040412 (Red Hat Linux 3.3.3-7)
(1 row)

CREATE TYPE returntype AS (a INT, b INT);
CREATE OR REPLACE FUNCTION return_multiple()
RETURNS setof returntype
LANGUAGE plpgsql
AS '
DECLARE
myvar returntype%rowtype;
BEGIN
myvar.a := 1;
myvar.b := 2;
RETURN NEXT myvar;
RETURN;
END;
';
SELECT * FROM return_multiple();
a | b
---+---
1 | 2
(1 row)

HTH,

Joe

Karl O. Pinc wrote:

Thanks! I was not declaring the variable %rowtype.
Adding that fixed the problem.

Ah yes, that works too. For the record:

CREATE TYPE returntype AS (a INT, b INT);
CREATE OR REPLACE FUNCTION return_multiple()
RETURNS returntype
LANGUAGE plpgsql
AS '
DECLARE
myvar returntype%rowtype;
BEGIN
myvar.a := 1;
myvar.b := 2;
RETURN myvar;
END;
';
SELECT * FROM return_multiple();
a | b
---+---
1 | 2
(1 row)

Joe

Thanks! I was not declaring the variable %rowtype.
Adding that fixed the problem.

On 2004.09.08 15:46 Joe Conway wrote:

Karl O. Pinc wrote:

Anybody got a better idea? Anybody know just when
this was fixed? If I knew I might be able to see about
getting our site upgraded. (I tried looking in the CVS
web interface, but was quickly daunted by the number of
source files.)

select version();
version
-------------------------------------------------------------------------
PostgreSQL 7.3.7 on x86_64-unknown-linux-gnu, compiled by GCC gcc
(GCC) 3.3.3 20040412 (Red Hat Linux 3.3.3-7)
(1 row)

CREATE TYPE returntype AS (a INT, b INT);
CREATE OR REPLACE FUNCTION return_multiple()
RETURNS setof returntype
LANGUAGE plpgsql
AS '
DECLARE
myvar returntype%rowtype;
BEGIN
myvar.a := 1;
myvar.b := 2;
RETURN NEXT myvar;
RETURN;
END;
';
SELECT * FROM return_multiple();
a | b
---+---
1 | 2
(1 row)

HTH,

Joe

Karl <kop@meme.com>
Free Software: "You don't pay back, you pay forward."
-- Robert A. Heinlein

"Karl O. Pinc" <kop@meme.com> writes:

Anybody got a better idea?

If they're all the same data type you could alternatively use an array. Which
is more convenient might depend on how much you want to throw around the
composite data type in intermediate code before peeking at the elements.

--
greg

Once I've gotten multiple values back from a plpgsql function,
how do I actually reference those values in another plpgsql
function? I've tried several syntaxes and keep getting errors.

Various attempts are below.

Thanks.

On 2004.09.08 15:59 Joe Conway wrote:

Ah yes, that works too. For the record:

CREATE TYPE returntype AS (a INT, b INT);
CREATE OR REPLACE FUNCTION return_multiple()
RETURNS returntype
LANGUAGE plpgsql
AS '
DECLARE
myvar returntype%rowtype;
BEGIN
myvar.a := 1;
myvar.b := 2;
RETURN myvar;
END;
';
SELECT * FROM return_multiple();
a | b
---+---
1 | 2
(1 row)

PostgreSQL 7.3.4 on i386-redhat-linux-gnu, compiled by GCC
i386-redhat-linux-gcc (GCC) 3.2.2 20030222 (Red Hat Linux 3.2.2-5)

CREATE FUNCTION return_multiple2()
RETURNS returntype
LANGUAGE plpgsql
AS '

DECLARE
myvar returntype%rowtype;
a INT;
b INT;

BEGIN

-- SELECT INTO a, b FROM return_multiple();
SELECT INTO a, b return_multiple();
myvar.a := a;
myvar.b := b;

-- SELECT INTO myvar return_multiple();

RETURN myvar;
END;
';

Karl <kop@meme.com>
Free Software: "You don't pay back, you pay forward."
-- Robert A. Heinlein