Hi there!  Can you show me a list of all of the cities including city IDs and city names?
select city_id,name from city
Oh, I am sorry about that.  Can you please show me a list of all of the cities located in counties that for which the county has a population over 20,000?
select name from city where county_id in ( select county_id from county_public_safety where population > 20000 )