Prepare > SQL > Basic Join > African Cities

African Cities | HackerRank

 

문제

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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.

 

=> CITY와 COUNTRY에서 아프리카 대륙의 도시 이름을 쿼리하라. 매칭키 주어짐.

 

 

 

 

코드

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SELECT CITY.NAME
FROM CITY
INNER JOIN COUNTRY ON CITY.COUNTRYCODE = COUNTRY.CODE
WHERE CONTINENT = 'Africa';

 

 

 

 

노트

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SELECT CT.NAME FROM CITY AS CT
    LEFT JOIN COUNTRY AS CN ON CT.COUNTRYCODE = CN.CODE
WHERE CN.CONTINENT = 'Africa';

 

 

두 번째 시도

SELECT CT.NAME 
FROM CITY AS CT INNER JOIN COUNTRY AS CN ON CT.COUNTRYCODE = CN.CODE
WHERE CN.CONTINENT = 'Africa';

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