https://www.hackerrank.com/challenges/asian-population/problem
Given the CITY and COUNTRY tables, query the sum of the populations of all cities where the CONTINENT is 'Asia'.
Note: CITY.CountryCode and COUNTRY.Code are matching key columns.
Input Format
The CITY and COUNTRY tables are described as follows:
- join two tables on countrycode ==> FROM CITY AS i JOIN COUNTRY AS o ON i.COUNTRYCODE=o.CODE
- query sum of populations of cities ==> SELECT SUM(i.POPULATION)
- where Continent is ‘Asia’ ==> WHERE o.CONTINENT=‘Asia’
SELECT SUM(C.POPULATION)
FROM CITY AS C
JOIN COUNTRY AS O ON C.COUNTRYCODE = O.CODE
WHERE O.CONTINENT = 'Asia';
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