PostgreSQL Cursor Error - postgresql

Question

I have the code:
DECLARE
cliente_cursor CURSOR FOR SELECT * FROM cliente;
cliente cliente.id_clie%TYPE;
nom cliente.nom_clie%TYPE;
BEGIN
OPEN cliente_cursor;
FETCH cliente_cursor INTO cliente, nom;
But I cannot run it. The following error appears:
ERROR: syntax error at or near "cliente"
LINE 3: cliente cliente.id_clie% TYPE;
        ^
I have the table "cliente" which has:
I want to create a cursor that shows only the content of the columns: id_clie, nom_clie of the previous table.
I have also used:
create or replace function facturas_cliente()
returns table (a int, b character varying(40))
language plpgsql as $$
declare
x cliente%rowtype ;
cliente_cursor cursor for select id_clie, nom_clie from cliente
order by id_clie;
begin
for x in cliente_cursor loop
return next x;
end loop;
end $$;
But I get the error:
ERROR: RETURN NEXT can not have parameters in a function with OUT parameters
LINE 9: return next x;
                    ^
What am I doing wrong?

Answer 1

First issue is strange. I tested on PostgreSQL 9.5 (but same code should to work on 9.2 and newer):
CREATE TABLE cliente(id_clie int, tel_clie varchar(15), dir_clie varchar(15));
DO $$
DECLARE
cliente_cursor CURSOR FOR SELECT * FROM cliente;
cliente cliente.id_clie%TYPE;
tel cliente.tel_clie%TYPE;
BEGIN
OPEN cliente_cursor;
END;
$$;
And it works without any issue. It looks like some mistyped error.
Second issue is clear. When function has a OUT variables or is declared as TABLE function, then RETURN NEXT has to be without expression. Returned composite value is based on actual context of OUT variables (columns declared in TABLE clause are OUT variables too). Your code should to be:
create or replace function facturas_cliente()
returns table (a int, b character varying(40))
language plpgsql as $$
declare
cliente_cursor cursor for select id_clie, nom_clie
from cliente
order by id_clie;
r record;
begin
for r in cliente_cursor -- a,b ~ OUT var declared in TABLE() clause
loop
a := r.id_clie; b := r.nom_clie;
return next; -- not: return next x;
end loop;
end $$;
This code can be reduced in PL/pgSQL two ways:
use a SQL function
create or replace function facturas_cliente()
returns table (a int, b character varying(40))
language sql as $$
select id_clie, nom_clie from cliente order by id_clie;
$$ language plpgsql;
use a RETURN QUERY statement in plpgsql:
create or replace function facturas_cliente()
returns table (a int, b character varying(40))
language sql as $$
BEGIN
RETURN QUERY SELECT id_clie, nom_clie
FROM cliente
ORDER BY id_clie;
RETURN;
END;
$$ language plpgsql;
Attention: these function can block a SQL optimizer if you use it in some complex query than trivial. Personally I don't like it. Use a view instead. It works like you need and there is no risk with optimization.
CREATE VIEW facturas_cliente
AS SELECT id_clie, nom_clie
FROM cliente
ORDER BY id_clie;