What is the maximum age of engineers?
select max(age) from person where job = 'engineer'
List all information for people older than this.
select * from person where age > (select min(age) from person where job = 'engineer')
Where are they all from?
select city from person where age > (select min(age) from person where job = 'engineer')
How many are there in total?
select count(*) from person where age > (select max(age) from person where job = 'engineer')