title: Using Oracle in select query
body: <p>Question: Given the CITY and COUNTRY tables, query the sum of the populations of all cities where the CONTINENT is 'Asia'.</p>
  
  <p>City table contains fields: CountryCode, Population
  Country table contains fields: Code, Continent
  (CITY.CountryCode and COUNTRY.Code are matching key columns.)</p>
  
  <p>I tried the following query: (I know this can be solved using Inner join)</p>
  
  <pre><code>Select sum(city.population) from city
  where city.countrycode in (Select code from Country where continent = 'Asia')
  </code></pre>
  
  <p>Hacker rank gives following error:
  ERROR at line 3: 
  ORA-00933: SQL command not properly ended</p>