On 7/5/19 3:32 PM, Tom Lane wrote:
Adrian Klaver <adrian.klaver@xxxxxxxxxxx> writes:
On 7/5/19 1:49 PM, PegoraroF10 wrote:
Sorry, the example I was thinking was this one, which works on Firebird,
using its way of writing, obviously.
create function myproc(id integer) returns I32 language sql as 'select $1';
On postgres ERROR: return type mismatch in function declared to return i32
What I mean is that Firebird sees I32 and integer as the same, Postgres
doesn´t.
Yeah, but if you reverse the casting you did in your first example it works:
create function myproc(id integer) returns I32 language sql as 'select
$1::i32';
CREATE FUNCTION
Yeah. This isn't an inherent property of Postgres, it's just that
SQL-language functions aren't defined to provide any implicit casting
of their results. The given expression must yield exactly the declared
function result type.
Aah:
CREATE OR REPLACE FUNCTION public.domain_test(id integer)
RETURNS i32
LANGUAGE plpgsql
AS $function$
BEGIN
RETURN id;
END;
$function$
;
test=> select domain_test(5);
domain_test
-------------
5
test=> select pg_typeof(domain_test(5));
pg_typeof
-----------
i32
(1 row)
So it works in plpgsql.
Most other places in PG are laxer and will automatically perform
implicit (and maybe assignment) casts for you. I don't remember
offhand whether there are good reasons for SQL functions to be
picky about this or it's just a shortage of round tuits. I have
a vague feeling that there might be some compatibility issues
in there, though.
regards, tom lane
--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx
