sql notes: hackerrank african cities

Problem

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 Format
The CITY and COUNTRY tables are described as follows:

Analysis

Join two tables on countrycode.

• join two tables ==> FROM CITY AS i JOIN COUNTRY AS o ON i.COUNTRYCODE=o.CODE
• query names of all cities ==> SELECT i.NAME
• where the Continent is ‘Africa’ ==> WHERE o.CONTINENT=‘Africa’

Solution

1

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

Link

African Cities
(中文版) SQL 笔记: Hackerrank African Cities