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  1. Prepare
  2. SQL
  3. Basic Join
  4. Average Population of Each Continent
  5. Discussions

Average Population of Each Continent

  • yashh_dubey03
     + 0 comments

    My solution used LEFT JOIN with COUNTRY as the left table and COALESCE to handle NULLs, so it actually included all continents as the problem stated. The accepted INNER JOIN solution only shows 5 out of 7 continents, which doesn’t seem like 'all' continents to me.

    SELECT CO.CONTINENT, COALESCE(ROUND(AVG(C.POPULATION), 0), 0)
FROM COUNTRY AS CO
LEFT JOIN CITY AS C
    ON C.COUNTRYCODE = CO.CODE
GROUP BY CO.CONTINENT;