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  1. Practice
  2. SQL
  3. Basic Join
  4. Asian Population
  5. Discussions

Asian Population

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  • raju_chapagain + 2 comments

    why there is no any other sql option (i.e. MSSQL, MYSQL)

    • abhinav_gta + 0 comments

      I was looking for the same. This is wierd

    • social38 + 0 comments

      exaclty same queries

  • pjbrydon + 1 comment

    Just a note in case anyone else keeps messing that up, you need to use single quotes for the string you're looking for. "Asia" returns an error using this SQL version...

    • lk00100100 + 2 comments

      You are doing god's work. Thank you.

  • RodneyShag + 9 comments

    MySQL solution

    From my HackerRank solutions.

    SELECT SUM(CITY.POPULATION) 
FROM CITY, COUNTRY
WHERE CITY.COUNTRYCODE = COUNTRY.CODE AND COUNTRY.CONTINENT = 'Asia';

    Let me know if you have any questions.

    • shubbubommu + 0 comments
      [deleted]
    • codegritty + 4 comments

      How come you didn't use JOIN for this?

      • RodneyShag + 1 comment

        I think the line:

        FROM CITY, COUNTRY

        actually ends up doing a join.

        HackerRank solutions.

        • plpratyusha + 1 comment

          It's actually the WHERE clause that makes this query a join ("WHERE CITY.COUNTRYCODE = COUNTRY.CODE")- that does the pairing of every row in the first table to the corresponding row in the second table. The FROM clause alone would yield a Cartesian product rather than a join.

          • codegritty + 2 comments

            I'm just wondering why we would use this particular 'WHERE' when I keep learning that we are moving onto JOIN and no longer WHERE anymore.

            Thoughts?

            • jacob_levine + 2 comments

              Here is a solution using JOIN:

              select sum(city.population)
from city
join country
on city.countrycode = country.code
where continent = 'Asia';
              • chandrika11 + 3 comments

                this code is not working

                • jyang316 + 0 comments

                  Did you try in MSSQL ? what error did you get if it didn't work ?

                • mathur_rajat5 + 0 comments
                  Select Sum(a.Population)
From City a inner join Country b
On a.Countrycode=b.Code
Where Continent = 'Asia';
                • stanescutiberiu1 + 0 comments

                  for mysql try And b.Continent='Asia' instead of Where Continent = 'Asia';

              • 16chen_george + 1 comment
                [deleted]
                • 16chen_george + 0 comments

                  This solutions sucks! It's not working.

            • ganesh_poloju3 + 0 comments

              select sum(city.population) from city join country on city.countrycode = country.code where country.continent = 'Asia'

      • cao123yudong + 1 comment

        I didnt use JOIN either:

        SELECT SUM(CITY.POPULATION) FROM CITY WHERE CITY.COUNTRYCODE IN (SELECT CODE FROM COUNTRY WHERE CONTINENT = 'ASIA')

        • yayafuture + 1 comment

          This is not join, this is subquery method. But they can achieve the same result.

          • sauce_chili + 0 comments

            yeah and he SAID that..

      • pooh_reddy + 0 comments

        It's a case of 'Self-Join' I guess.

      • kmnaveen101 + 0 comments

        @codegritty he is using a type of join called cross join which is inefficient in practice.

    • sluongng + 4 comments

      I wonder between your solution and mine

      SELECT SUM(POPULATION) FROM CITY WHERE COUNTRYCODE IN (SELECT CODE FROM COUNTRY WHERE CONTINENT = 'Asia')

      which has better performance? or same?

      • RodneyShag + 0 comments

        I'm not sure.

      • jyang316 + 0 comments

        think of a select like it's an if statement. If you have 2 or more if's, it takes more time to think. If you join the the table it will do one lookup amongst both tables. Hope this helps !

      • vivek_gupta_blue + 0 comments

        I guess the above has better performance as the object is specified with attribute.

      • yayafuture + 0 comments

        In general, join is more efficient. Here is one reference https://stackoverflow.com/questions/2577174/join-vs-sub-query

    • sahilkamboj334 + 1 comment

      why only "city.population".we have to calculate sum of population of both the tables.Why query "select sum(city.population,country.population) from city join country where CITY.CountryCode = COUNTRY.Code and continent='asia';" not working.Can you please explain.

      • RodneyShag + 0 comments

        Hi. The problem says to "query the sum of the populations of all CITIES..." so we don't need the country populations.

        HackerRank solutions.

    • alphac + 0 comments

      If no. of tables and joining was more, then aliasing would come handy.

    • ReadLearn + 0 comments

      yes this works

    • diegomsaiz + 0 comments

      Thank you very much indeed for your help. The query had a little complexity (at least for myself) and I just couldn't find the way out.

    • kushal_23dec + 1 comment

      NOT WORKING

      • RodneyShag + 0 comments

        Please make sure you are using MySQL, and solution should work.

        HackerRank solutions.

    • sauce_chili + 0 comments
      [deleted]

  • marinskiy + 0 comments

    Here is Oracle solution from my HackerrankPractice repository:

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

    Feel free to ask if you have any questions :)

  • bmackin1 + 0 comments

    Two ways that work in Oracle:

    SELECT SUM(cty.POPULATION) FROM CITY cty, COUNTRY cry
WHERE cty.COUNTRYCODE = cry.CODE
AND cry.CONTINENT = 'Asia';

    SELECT SUM(cty.POPULATION) FROM CITY cty JOIN COUNTRY cry
ON cty.COUNTRYCODE = cry.CODE
WHERE cry.CONTINENT = 'Asia';

  • AlexNetkachov + 1 comment

    ERROR: ORA-09925: Unable to create audit trail file Linux-x86_64 Error: 28: No space left on device Additional information: 9925 ORA-01075: you are currently logged on

    Please fix :)

    • pankajdesai18 + 0 comments

      same issue with me also.

  • VimalKumar_s + 1 comment

    I can't select other language, SQL server??

    • abhiranjanChallenge Author + 1 comment

      Hi, there's only one language enabled for this challenge. Sorry for the inconvenience. We are working on providing support in other languages.

      • jewelhuq + 1 comment

        Please ad mssql or mysql

        • aswinramakrish + 0 comments

          This is a simple query. It shouldn't make much of a difference to execute in Oracle.

          TIP: End the query with semi-color and be explicit with the type of join.

  • dennis_furrer + 0 comments

    SELECT SUM(CITY.POPULATION) FROM CITY JOIN COUNTRY ON CITY.COUNTRYCODE = COUNTRY.CODE WHERE CONTINENT = "Asia";

  • me_rishiverma + 1 comment

    why i'm not getting any other language option other than oracle ?

    • AshwinGShenoyAsked to answer + 1 comment

      I am also getting only oracle. I think for this all other options are not available

      • ms4392 + 0 comments

        3 months after your post, I'm still getting only oracle option.

  • anirudherabelly + 1 comment

    This worked for me(ORACLE). SELECT SUM(City.Population) FROM City INNER JOIN Country ON City.COUNTRYCODE=Country.Code WHERE Country.Continent='Asia';

    • Roman_Krasavtsev + 0 comments

      The same for MS SQL :)

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