Question about odbc link to Oracle database from PostgreSQL

Dear All

I have a question regarding to odbc link,

I had a PostgreSQL database and an Oracle database, now I have created
a dblink to Oracle database base on odbc link.

in Oracle database, I created a user named ORATEST, and create a table
named TEST as ORATEST user.

SQL> select user_name,score from test;

USER_NAME SCORE
-------------------- ----------
kevin 99
fred 98

now I have created the database link to Oracle database over odbc link
and get success.

tora=# select odbclink.connect('orcl', 'oratest', 'oratest');
connect
---------
1
(1 row)

tora=# select odbclink.connect('DSN=orcl;UID=oratest;PWD=oratest;');
connect
---------
2
(1 row)

tora=# select * from odbclink.connections();
id | connected | dsn | uid | pwd | connstr
----+-----------+------+------+------+-----------------------------
1 | t | orcl | oratest| oratest|
2 | t | | | | DSN=orcl;UID=oratest;PWD=oratest;
3 | f | | | |
4 | f | | | |

but the problem is that I can not execute the SQL execute it.

tora=# select odbclink.query(1, 'SELECT * FROM test') as
result(user_name text,score number);
ERROR: syntax error at or near "("
LINE 1: ... odbclink.query(1, 'SELECT * FROM test') as result(user_name...
^
tora=# select * odbclink.query(1, 'SELECT * FROM test') ;
ERROR: syntax error at or near "odbclink"
LINE 1: select * odbclink.query(1, 'SELECT * FROM test') ;
^
tora=# select * from odbclink.query(2,'SELECT SYSDATE FROM DUAL');
ERROR: a column definition list is required for functions returning "record"
LINE 1: select * from odbclink.query(2,'SELECT SYSDATE FROM DUAL');
^
tora=# select * from odbclink.query(1,'SELECT SYSDATE FROM DUAL');
ERROR: a column definition list is required for functions returning "record"
LINE 1: select * from odbclink.query(1,'SELECT SYSDATE FROM DUAL');
^
tora=#

does anyone mind to give me hint?

a big thanks

Hsien-Wen