[SQL] Average Population of Each Continent

✅ Average Population of Each Continent

📝 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.

Input Format

The CITY and COUNTRY tables are described as follows:

💻 풀이

SELECT
    B.CONTINENT,
    FLOOR(AVG(A.POPULATION))
FROM CITY AS A INNER JOIN COUNTRY AS B
    ON A.COUNTRYCODE = B.CODE
GROUP BY B.CONTINENT;