OUTER JOIN

Hallo,

I need to port some SQL from Oracle to PostgreSQL v7.2, but I am finding
problems with outer joins.

Here are the tables:
select * from shift_typeid | order_num | from_time | to_time  | disabled
----+-----------+-----------+----------+---------- 1 |         1 | 06:00:00  | 14:00:00 | f 2 |         2 | 14:00:00  |
22:00:00| f 3 |         3 | 22:00:00  | 06:00:00 | t 6 |         6 | 00:00:00  | 23:00:00 | f
 

select * from shift_descapp_language_id | shift_type_id | description
-----------------+---------------+-------------              1 |             1 | Morning              1 |             2
|Afternoon              1 |             3 | Night              2 |             6 | SHIFT_DE              1 |
6 | SHIFT_EN
 

and here is the SQL for Oracle:
SELECT ST.id, ST.order_num, ST.from_time, ST.to_time, ST.disabled,
SD.descriptionFROM shift_type ST, shift_desc SDWHERE ST.id = SD.shift_type_id(+) AND SD.app_language_id(+) = 2ORDER BY
ST.order_num

The expected result should be:id | order_num | from_time | to_time  | disabled | description
----+-----------+-----------+----------+----------+------------- 1 |         1 | 06:00:00  | 14:00:00 | f        | 2 |
      2 | 14:00:00  | 22:00:00 | f        | 3 |         3 | 22:00:00  | 06:00:00 | t        | 6 |         6 | 00:00:00
|23:00:00 | f        | SHIFT_DE
 
with description populated with NULL, as app_language_id not found.


It seems that Oracle's outer joins work on the basis the single record,
while PostgreSQL don't.
How to do it?

Thank you for your attention,
Marco Roda