sql - group by関数でのcount（*）の適切な使用

Question

SQLでは、countryのような列でGROUP BY関数を使用できますか？（これはchar / varcharになります）

SELECT country, population, COUNT(*) AS count_cities
FROM list_of_cities
GROUP BY country;

これを書くためのより良い方法は何でしょうか？

Answer 1

SELECT country, SUM(population) AS country_population, COUNT(*) AS count_cities 
FROM list_of_cities 
GROUP BY country;