MySQL Query help

[Sönke Petersen]

Hi there, I'm pretty new to mysql. I'm trying to make a query concerning 2 given tables.

Destination:
| Letter-ID | Destination-Country | [..] and

Addresser:
| Letter-ID | Addresser-ID | [..]

Letter-ID and Addresser-ID are unique.

I'm trying to list all addressers (Addresser-ID) who have been writing to addressees in at least 2 different countries. The countries should be in the list, too:
| Addresser-ID | Destination-Country |
| 1 | England |
| 1 | Denmark |
| 1 | Portugal |
| 3 | England |
| 3 | India |
...

Right now, I've no access to the database, but I'm trying to work out a query.

SELECT addresser-id, destination-country
FROM destination a INNER JOIN addresser b ON ( a.letter-id = b.letter-id)
GROUP BY addresser-id, destination-country
HAVING COUNT(addresserid) > 1;

I'm not sure, if the inner join solution (if working) is the best way to do it. Somebody got a better idea?

Thanks in advance.