Select count / duplicates

Question

I have a table with all U.S. zip codes. each row contains the city and state name for the zip code. I\'m trying to get a list of cities that show up in multiple states. This

Answer 1

First group on state and city, then group the result on city:

select City
from (
  select State, City
  from ZipCode
  group by State, City
) x
group by City
having count(*) > 1