Re: OUTER JOIN

On Thursday 17 Apr 2003 3:21 pm, Marco Roda wrote:
> Hallo,
>
> I need to port some SQL from Oracle to PostgreSQL v7.2, but I am finding
> problems with outer joins.
[snip]
> and here is the SQL for Oracle:
> SELECT ST.id, ST.order_num, ST.from_time, ST.to_time, ST.disabled,
> SD.description
>  FROM shift_type ST, shift_desc SD
>  WHERE ST.id = SD.shift_type_id(+) AND SD.app_language_id(+) = 2
>  ORDER 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?

SELECT ST.id, ST.order_num, ST.from_time, ST.to_time, ST.disabled,
SD.description
FROM shift_type ST LEFT JOIN shift_desc SD  ON ST.id=SD.shift_type_id AND SD.app_language_id=2
ORDER BY ST.order_num;

That seems to work. Out of curiosity, what were you trying?

--  Richard Huxton