Advanced SQL Your-Turn Solutions

YOUR TURN #1

select C1.city, C2.city, C1.temperature
from Cities C1, Cities C2
where C1.temperature = C2.temperature
and C1.city < C2.city

YOUR TURN #2

select city, Cities.country
from Cities, Countries
where Cities.country = Countries.country
and population < 2

select city, country
from Cities
where country in (select country from Countries where population < 2)

select country
from Countries
where country not in (select country from Cities where temperature > 6)

YOUR TURN #3

select country
from Cities
group by country
having avg(longitude) < (select avg(longitude) from Cities)
and avg(latitude) > (select avg(latitude) from Cities)