Find the average height and weight for all males (sex is M).
select avg ( height ), avg ( weight ) from people where sex = 'M'
How many male people are on the table?
select count ( * ) from people where sex = 'M'
Which person has the highest height?
select * from people order by height desc limit 1
How many female people are on the list?
select count ( * ) from people where sex = 'F'