What is the average age of all the male students (sex with M) from each city?
select avg ( age ), city_code from student where sex = 'M' group by city_code
What are the average number of all the male students (sex with M) from each city?
select count ( * ), city_code from student where sex = 'M' group by city_code
What is his age?
select age from student where city_code = 'ATL'
What is the average age of all the female students (sex with F) from each city?
select avg ( age ), city_code from student where sex = 'F' group by city_code