What is the laargest white percentage among all cities?
select max(white) from city
How many cities have a white percentage of more than 90?
select count(*) from city where white > 90
What is the id of the county this city is located in?
select county_id from city where white > 90
What is this county's crime rate?
select t2.crime_rate from city as t1 join county_public_safety as t2 on t1.county_id = t2.county_id where t1.white > 90