[SQL] Population Census

✅ Population Census

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📝 문제

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:

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💻 풀이

SELECT SUM(A.POPULATION)
FROM CITY AS A INNER JOIN COUNTRY AS B
    ON A.COUNTRYCODE = B.CODE
WHERE B.CONTINENT = 'Asia';

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