[SQL] two table comparison: find a mismatch?

[Web Manager]

Hello,

here is to table:
                               Table "city"
   Attribute    |    Type     |                  Modifier
----------------+-------------+---------------------------------------------
 city_id        | smallint    | not null default
nextval('seq_city'::text)
 region_id      | smallint    |
 region_tour_id | smallint    |
 country_id     | smallint    |
 name_fr        | varchar(40) |
 name           | varchar(40) |
 url_id         | smallint    |


                             Table "region"
 Attribute |    Type     |                   Modifier
-----------+-------------+----------------------------------------------
 region_id | smallint    | not null default nextval('seq_region'::text)
 country_id| smallint    |
 name_fr   | varchar(40) |
 name      | varchar(40) |
 address   | boolean     |
 url_id    | smallint    | 


I whant to fins a "hole" in the linkage... a region number in the city
table is not in the region table any more.

How can I do that?

Where is the city.region_id <> region.region_id

Thanks!
-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Marc Andre Paquin