[SQL] DIfference between max() and greatest() ?

[Ruben Gouveia]

What is the difference between these two. I know that max() is an aggregate
function

select model,count(distinct cars)
from rc_cars
where greatest(baught,returned) < current_date - integer '1'
group by model;

Do i need to have a max () around a greatest() to make sure i get the most
recent of the two.

select model,count(distinct cars)
from rc_cars
where max(greatest(baught,returned)) < current_date - integer '1'
group by model;