SQLZOO:SUM and COUNT

1.Show the total population of the world.

world(name, continent, area, population, gdp)

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 (‘Estonia’, ‘Latvia’, ‘Lithuania’)

select sum(population)
from world
where name in ('Estonia', 'Latvia', 'Lithuania');

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 that have a total population of at least 100 million.

select continent
from world
group by continent
having sum(population)>=100000000;