Description

Submission

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

References

1. https://www.mysqltutorial.org/mysql-inner-join.aspx/
2. https://stackoverflow.com/questions/17759687/cross-join-vs-inner-join-in-sql
3. https://www.w3schools.com/sql/sql_join_inner.asp