allowed variable names in functions?

Hello

it works in my 8.1

postgres=# CREATE LANGUAGE plpgsql;
CREATE LANGUAGE
postgres=# create or replace function foo(a int) returns void as
$$declare c2 real; c2div real; begin c2div := 10.9; end; $$ language
plpgsql;
CREATE FUNCTION
postgres=# select foo(10);
foo
-----

(1 row)
Regards
Pavel Stehule

2008/6/30 A B <gentosaker@gmail.com>:

Then my assumption was wrong.
Here is the entire function and it fails with the names
c2,c2div,c3,c3div, but if names are changed, it works!
(by works I mean I get the "hello" lines printed) There is nothing
wrong with the select statement either, that works fine if I run it
stand-alone, or with the names of c2,c2div,c3,c3div changed.

CREATE OR REPLACE FUNCTION foo(pid_ INTEGER) RETURNS void AS $$
DECLARE
c2 REAL;
c2div REAL;
c3 REAL;
c3div REAL;
weights RECORD;
tmp RECORD;
retval RECORD;
t RECORD;
BEGIN
RAISE NOTICE 'starting...';
FOR tmp IN SELECT id,c2,c3 FROM Master WHERE pid=pid_ AND c3 !=0 LOOP
RAISE NOTICE 'hello %',tmp.id;
END LOOP;
RETURN;
END; $$ LANGUAGE plpgsql;

2008/6/30 Pavel Stehule <pavel.stehule@gmail.com>:

By changing c2,c3,etc. to something else xc2,xc3, etc. it worked!
So was the problem that I refered to the same names in the SELECT statement?

2008/6/30 A B <gentosaker@gmail.com>:

am Mon, dem 30.06.2008, um 12:38:40 +0200 mailte A B folgendes:

Then my assumption was wrong.
Here is the entire function and it fails with the names
c2,c2div,c3,c3div, but if names are changed, it works!
(by works I mean I get the "hello" lines printed) There is nothing
wrong with the select statement either, that works fine if I run it
stand-alone, or with the names of c2,c2div,c3,c3div changed.

CREATE OR REPLACE FUNCTION foo(pid_ INTEGER) RETURNS void AS $$
DECLARE
c2 REAL;
c2div REAL;
c3 REAL;
c3div REAL;
weights RECORD;
tmp RECORD;
retval RECORD;
t RECORD;
BEGIN
RAISE NOTICE 'starting...';
FOR tmp IN SELECT id,c2,c3 FROM Master WHERE pid=pid_ AND c3 !=0 LOOP
RAISE NOTICE 'hello %',tmp.id;
END LOOP;
RETURN;
END; $$ LANGUAGE plpgsql;

Don't use the same names for plpgsql-variables and for column names.

Andreas
--
Andreas Kretschmer
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GnuPG-ID: 0x3FFF606C, privat 0x7F4584DA http://wwwkeys.de.pgp.net

I see one big problem. You have colision between column and variable
names! When you has SQL inside function use prefix for variables or
use qualified names.

DECLARE a varchar;
BEGIN
FOR a IN SELECT a FROM ... -- is bug

you have to do
DELARE _a varchar;
BEGIN
FOR _a IN SELECT t.a FROM tab t ...

Regards
Pavel Stehule

2008/6/30 A B <gentosaker@gmail.com>:

On Mon, Jun 30, 2008 at 12:44:31PM +0200, A B wrote:

By changing c2,c3,etc. to something else xc2,xc3, etc. it worked!
So was the problem that I refered to the same names in the SELECT statement?

Yes.

Karsten
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E167 67FD A291 2BEA 73BD 4537 78B9 A9F9 E407 1346

Thank you both! :-)

But there not any problem with returning values with code like this

DECLARE
retval RECORD;

retval.c2 := ....
RETRUN NEXT retval;

if c2 is a field on some table?

2008/6/30 Karsten Hilbert <Karsten.Hilbert@gmx.net>:

But there not any problem with returning values with code like this

DECLARE
retval RECORD;

retval.c2 := ....
RETRUN NEXT retval;

if c2 is a field on some table?

Oh, that seems also to be problematic.

A B wrote:

Here is the entire function and it fails with the names
c2,c2div,c3,c3div, but if names are changed, it works!
(by works I mean I get the "hello" lines printed) There is nothing
wrong with the select statement either, that works fine if I run it
stand-alone, or with the names of c2,c2div,c3,c3div changed.

CREATE OR REPLACE FUNCTION foo(pid_ INTEGER) RETURNS void AS $$
DECLARE
c2 REAL;
c2div REAL;
c3 REAL;
c3div REAL;
weights RECORD;
tmp RECORD;
retval RECORD;
t RECORD;
BEGIN
RAISE NOTICE 'starting...';
FOR tmp IN SELECT id,c2,c3 FROM Master WHERE pid=pid_ AND c3 !=0 LOOP
RAISE NOTICE 'hello %',tmp.id;
END LOOP;
RETURN;
END; $$ LANGUAGE plpgsql;

That is because c2 and c3 in the SELECT statement are replaced with
the variables before the SQL statement is executed.

See the documentation:
http://www.postgresql.org/docs/current/static/plpgsql-implementation.html#PLPGSQL-VAR-SUBST

You should qualify the column names:

SELECT master.id, master.c2, master.c3 FROM master WHERE ... AND master.c3 <> 0

Yours,
Laurenz Albe