5_sum.sql

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

-- List all the continents - just once each.
SELECT continent FROM world GROUP BY continent;

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

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

-- What is the total population of ('Estonia', 'Latvia', 'Lithuania')
SELECT SUM(population)
FROM world
WHERE name IN ('Estonia', 'Latvia', 'Lithuania');

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

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

-- For each continent show the continent and number of countries with populations of at least 10 million.