[해커랭크 SQL] Basic Join - Average Population of Each Continent

❓ Question
https://www.hackerrank.com/challenges/average-population-of-each-continent

Average Population of Each Continent | HackerRank

 

❗ Answer

SELECT country.continent, FLOOR(AVG(city.population))
    FROM city
    INNER JOIN country
            ON city.countrycode = country.code
    GROUP BY country.continent;

📌 Discussion

• join 후 group by로 continent별로 묶고 avg 집계 후 floor로 버림