Hi,
we have found a way to make pl/pgsql throw an error for
a legitimate use case that works in plain SQL.
Minimal test case:
create table x1 (id serial primary key, d timestamptz);
create table x2 (id serial primary key, d timestamptz);
insert into x2 (d) values ('now');
create type mytype as (id bigint, d timestamptz);
Casting a set of values to "mytype" works in SQL:
=# select (max(id),min(d))::mytype from x2; row
------------------------------------- (1,"2012-04-24 09:04:07.475315+02")
(1 row)
=# select (max(id),min(d))::mytype from x1; row
----- (,)
(1 row)
Even empty data in plain text casted to "mytype" works
and individual fields can be tested for IS NULL:
=# select '(,)'::mytype; mytype
-------- (,)
(1 row)
=# select ('(,)'::mytype).id is null; ?column?
---------- t
(1 row)
Now, try this from PL/PGSQL:
create or replace function testfunc1() returns mytype as $$declare v_sql text; mt mytype;
begin v_sql := 'select (max(id),min(d))::mytype from x1'; execute v_sql into mt; return mt;
end;$$ language plpgsql;
=# select testfunc1();
ERROR: invalid input syntax for integer: "(,)"
CONTEXT: PL/pgSQL function "testfunc1" line 6 at EXECUTE statement
The same error happens with table "x2" with data in it:
create or replace function testfunc2() returns mytype as $$declare v_sql text; mt mytype;
begin v_sql := 'select (max(id),min(d))::mytype from x2'; execute v_sql into mt; return mt;
end;$$ language plpgsql;
=# select testfunc2();
ERROR: invalid input syntax for integer: "(1,"2012-04-24 09:04:07.475315+02")"
CONTEXT: PL/pgSQL function "testfunc2" line 6 at EXECUTE statement
Same happens also with non-dynamic queries:
create or replace function testfunc1a() returns mytype as $$declare mt mytype;
begin select (max(id),min(d))::mytype into mt from x1; return mt;
end;$$ language plpgsql;
=# select testfunc1a();
ERROR: invalid input syntax for integer: "(,)"
CONTEXT: PL/pgSQL function "testfunc1a" line 4 at SQL statement
create or replace function testfunc2a() returns mytype as $$declare mt mytype;
begin select (max(id),min(d))::mytype into mt from x2; return mt;
end;$$ language plpgsql;
=# select testfunc2a();
ERROR: invalid input syntax for integer: "(1,"2012-04-24 09:04:07.475315+02")"
CONTEXT: PL/pgSQL function "testfunc2a" line 4 at SQL statement
Best regards,
Zoltán Böszörményi
--
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Zoltán Böszörményi
Cybertec Schönig& Schönig GmbH
Gröhrmühlgasse 26
A-2700 Wiener Neustadt, Austria
Web: http://www.postgresql-support.de http://www.postgresql.at/
