05_sum_and_count.sql

-- 1. Show the total population of the world.
SELECT SUM(population) pop_world
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) gdp_Africa
FROM world
WHERE continent = 'Africa'

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

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

-- 6. For each continent show the continent and number of countries.
SELECT continent, COUNT(name) num_countries
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) num_countries
FROM world
WHERE population >= 10E6
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) >= 100E6