Postgresql游标CURSOR

CREATE OR REPLACE FUNCTION cursor_demo()
RETURNS refcursor AS
$BODY$

DECLARE

cur CURSOR FOR select id , totalspace from aaa where discardflag = '0';
v_id int;
v_totalspace int;
begin
open cur;
FETCH  cur into v_id,v_totalspace ;
while found loop
insert into a values (v_id,v_totalspace);
FETCH next from  cur into v_id,v_totalspace ;

end loop;
RETURN cur ;
close cur;
END;
$BODY$
LANGUAGE plpgsql;