[해커랭크] Average Population of Each Continent

https://www.hackerrank.com/challenges/average-population-of-each-continent/problem?isFullScreen=true&h_r=next-challenge&h_v=zen 

Average Population of Each Continent | HackerRank

 

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.

 

round 써야하는 문제인 줄 알았는데 round 쓰면 오류난다,,,

floor로 써줘야 함

 

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