Sum a column and group it, then divide by a field in another table

Question

I have two tables, one that looks like this:

The other has the countries' populations:

I would like to sum up the revenue by country (I know how to do this part, e.g Select Sum(Revenue), Country from COMPANIES GROUP BY Country;)

and then divide it by the population from the other table to get per capital revenue , so the final result should be

Answer 1

If you have this set: sql_mode=only_full_group_by

Then it will need to be like this:

SELECT companies.country, 
       round(sum(revenue) / country.population, 2) as RevPerCap  
FROM companies
join country on country.name = companies.country  
group by companies.country, country.population