--
-- acs_event__get_description/1
--
create or replace function acs_event__get_description(
  integer
) returns text as $$
	-- acs_events.description%TYPE
declare
       get_description__event_id   alias for $1;
       v_description		    acs_events.description%TYPE; 
begin

       select coalesce(e.description, a.description) into v_description
       from   acs_events e
       left join acs_activities a
       on  (e.activity_id = a.activity_id)
       where  e.event_id = get_description__event_id;

       return v_description;

end;$$ language plpgsql;