In the World population practice, in question 4, I did this:
//with uni as (select * from countries
left join population_years
on = population_years.country_id)

select sum (population) from uni
where continent = ‘Oceania’ and year = 2005;//

And the codecademy answer is this:
//SELECT SUM(population) FROM population_years
INNER JOIN countries ON = population_years.country_id
WHERE year = 2005
AND continent = ‘Oceania’;//

And the answer was correct.

So, what is the computing difference?

I honestly don’t know xD!!

Will you post a link to the problem, please?

What does this line of code do? = population_years.country_id