5_sum_and_count.sql

-- # 1. Show the total population of the world.
SELECT SUM(population)
FROM world;

-- # 2. List all the continents - just once each.
SELECT DISTINCT continent
FROM world;

-- # 3. Give the total GDP of Africa
SELECT SUM(gdp)
FROM world
WHERE continent = 'Africa';

-- # 4. How many countries have an area of at least 1000000
SELECT COUNT(name)
FROM world
WHERE area >= 1000000;

-- # 5. What is the total population of ('France','Germany','Spain')
SELECT SUM(population)
FROM world
WHERE name IN ('France', 'Germany', 'Spain');

-- # 6. For each continent show the continent and number of countries.
SELECT continent, COUNT(name)
FROM world
GROUP BY continent;

-- # 7. For each continent show the continent and number of countries
-- # with populations of at least 10 million.
SELECT continent, COUNT(name)
FROM world
WHERE population >= 10000000
GROUP BY continent;

-- # 8. List the continents with total populations of at least 100
-- # million.
SELECT continent
FROM world
GROUP BY continent
HAVING SUM(population) >= 100000000;