SUM AND COUNT

1.

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Show the total population of the world.

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

SELECT SUM(population)
FROM world

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2.

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List all the continents - just once each.

SELECT continent
FROM world
GROUP BY continent

3.

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Give the total GDP of Africa

SELECT SUM(GDP)
FROM world
WHERE continent LIKE 'Africa'

4.

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How many countries have an area of at least 1000000

SELECT COUNT(name)
FROM world
WHERE area >= 1000000

5.

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What is the total population of ('Estonia', 'Latvia', 'Lithuania')

SELECT SUM(population)
FROM world
WHERE name IN ('Estonia', 'Latvia', 'Lithuania')

6.

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For each continent show the continent and number of countries.

SELECT continent, COUNT(name)
FROM world
GROUP BY continent

7.

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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.

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List the continents that have a total population of at least 100 million.

SELECT continent
FROM world
GROUP BY continent
HAVING SUM(population) >= 100000000