Problem
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:
Code
#1
Idea
구해야 하는 것 : continents 의 이름(country.continent) 과 그 continents 에 속한 city 의 populations(city.population) 의 평균의 내림값
Code
select country.continent, floor(avg(city.population))
from city
join country
on city.countrycode = country.code
group by country.continent
SQL
복사
Solution
Commentary
avg 와 floor 몰랐다.