✅ 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;