Consider two relation instances below, with the following schemas:

Country (country_name, continent); City (city_name, country_name, isCapital, population).

For each question (a)-(c) below, write a SQL query for an Oracle system

Country

Country_name	Continent
US	North America
Canada	North America
England	Europe
Germany	Europe
France	Europe
Mali	Africa

City

City_Name	Country_Name	isCapital	Population
New York, NY	US	no	8,000,000
Washington, DC	US	yes	600,000
Philadelphia, PA	US	no	1,500,000
Ottawa	Canada	yes	800,000
Toronto	Canada	no	2,500,000
Berlin	Germany	yes	3,500,000
Hamburg	Germany	no	2,000,000
Bonn	Germany	no	300,000
Paris	France	yes	2,000,000
Lyon	France	no	700,000
Bamako	Mali	yes	2,000,000
Timbuktu	Mali	no	50,000
Mopti	Mali	no	100,000

QUESTIONS (a-c)

(a) List the average population and number of all European cities with population of more than 600,000.

(b) Identify the city with largest population for each country. List its country name, and the population.

(c) For each country, list its name and belonging continent, along with its total population that is over 1 million. Also sort the result by the total population in descending order.