SUM and COUNT.sql

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

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

#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 DISTINCT 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.
SELECT DISTINCT continent, COUNT(name)
FROM world
WHERE population >= 10000000
GROUP BY continent;

#List the continents that have a total population of at least 100 million.
SELECT continent
FROM world
GROUP BY continent
HAVING SUM(population) >= 100000000;