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DataBase/Hackers Rank

• HackerRank - Average Population of Each Continent

  DataBase/Hackers Rank 2024. 10. 7. 23:05

  Given the CITY and COUNTRY tables, query the names of all the continents (COUNTRY.Continent) and their respective average city populations (CITY.Population) rounded down to the nearest integer.Note: CITY.CountryCode and COUNTRY.Code are matching key columns.Input FormatThe CITY and COUNTRY tables are described as follows:      AnswerSELECT country.continent , FLOOR(AVG(city.population))FROM c..

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• HackerRank - Population Census

  DataBase/Hackers Rank 2024. 10. 7. 23:01

  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 FormatThe CITY and COUNTRY tables are described as follows: AnswerSELECT SUM(city.population)FROM city INNER JOIN country ON city.countrycode = country.codeWHERE country.continent = 'Asia'  Result27028484

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• African Cities - INNER JOIN

  DataBase/Hackers Rank 2024. 10. 7. 22:58

  Given the CITY and COUNTRY tables, query the names of all cities where the CONTINENT is 'Africa'.Note: CITY.CountryCode and COUNTRY.Code are matching key columns.Input FormatThe CITY and COUNTRY tables are described as follows:  AnswerSELECT city.nameFROM city INNER JOIN country ON city.countrycode = country.codeWHERE country.continent = 'Africa'  ResultYour Output (stdout)QinaWarraq al-ArabK..

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• HackerRank - Type of Triangle

  DataBase/Hackers Rank 2024. 9. 30. 22:58

  Write a query identifying the type of each record in the TRIANGLES table using its three side lengths. Output one of the following statements for each record in the table:Equilateral: It's a triangle with 3 sides of equal length.Isosceles: It's a triangle with 2 sides of equal length.Scalene: It's a triangle with  3 sides of differing lengths.Not A Triangle: The given values of A, B, and C don't..

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• HackersRank - Population Density Difference 문제

  DataBase/Hackers Rank 2024. 8. 2. 00:26

  SELECT 절에서 자연스럽게 *, +, -, / 연산이 가능하다.SELECT MAX(population) - MIN(population) FROM city

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• HackersRank - Average Population 문제

  DataBase/Hackers Rank 2024. 8. 1. 23:42

  CEIL() 올림FLOOR() 내림ROUND() 반올림SELECT FLOOR(AVG(population)) FROM city;

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• HackersRank - Revising Aggregations - The Count Function 문제

  DataBase/Hackers Rank 2024. 8. 1. 23:38

  100,000 초과의 경우이니 > 를 사용SELECT COUNT(*) FROM city WHERE population > 100000;

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• HackersRank - Revising Aggregations - The Sum Function문

  DataBase/Hackers Rank 2024. 8. 1. 23:35

  SELECT SUM(population) FROM city WHERE district = "California";

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