Average Population of Each Continent / HackerRank, SQL, MySQL

문제

Given the CITY and COUNTRY tables, query the names of all the continents (COUNTRY.Continent) and their respective average city populations (CITY.Population) rounded down to the nearest integer.

Note: CITY.CountryCode and COUNTRY.Code are matching key columns.

 

 

제출답안(MySQL)

SELECT continent, FLOOR(AVG(ct.population))
FROM city as ct JOIN country ctr ON ct.countrycode = ctr.code
GROUP BY continent

 

문제 바로가기(MySQL)