Bigger than Russia

List each country name where the population is larger than that of ‘Russia’.

SELECT name FROM world
WHERE population >
     (SELECT population FROM world
      WHERE name='Russia');

Richer than UK

Show the countries in Europe with a per capita GDP greater than ‘United Kingdom’.

SELECT name FROM world
WHERE continent = 'EUROPE' AND gdp/population >
    (SELECT gdp/population FROM world
      WHERE name='United Kingdom');

Neighbors of Argentina and Australia

List the name and continent of countries in the continents containing either Argentina or Australia. Order by name of the country.

SELECT name, continent FROM world
WHERE continent IN ('South America', 'Oceania')
ORDER BY name;

Between Canada and Poland

Which country has a population that is more than Canada but less than Poland? Show the name and the population.

SELECT name, population FROM world
WHERE population >
    (SELECT population FROM world
    WHERE name = 'Canada')
AND population <
    (SELECT population FROM world
    WHERE name = 'Poland');

Percentages of Germany

Germany (population 80 million) has the largest population of the countries in Europe. Austria (population 8.5 million) has 11% of the population of Germany.

Show the name and the population of each country in Europe. Show the population as a percentage of the population of Germany.

SELECT name, CONCAT(ROUND(population/(SELECT population FROM world
WHERE name = 'Germany') * 100), '%') FROM world
WHERE continent = 'Europe';

Bigger than every country in Europe

Which countries have a GDP greater than every country in Europe? [Give the name only.] (Some countries may have NULL gdp values)

SELECT name FROM world
WHERE gdp >= ALL(SELECT gdp FROM world
                    WHERE continent = 'Europe' AND gdp>0)
AND continent != 'Europe';

Largest in each continent

Find the largest country (by area) in each continent, show the continent, the name and the area:

SELECT continent, name, area FROM world x
WHERE area >= ALL
  (SELECT area FROM world y
      WHERE y.continent=x.continent
          AND area>0);

First country of each continent (alphabetically)

List each continent and the name of the country that comes first alphabetically.

SELECT continent, name FROM world x
WHERE name <= ALL
  (SELECT name FROM world y
      WHERE y.continent=x.continent);

Difficult Questions That Utilize Techniques Not Covered In Prior Sections

Find the continents where all countries have a population <= 25000000. Then find the names of the countries associated with these continents. Show name, continent and population.

SELECT name, continent, population FROM world
WHERE continent IN
  (SELECT continent FROM world x
    WHERE
      (SELECT MAX(population) FROM world y
        WHERE x.continent = y.continent) <= 25000000);

Some countries have populations more than three times that of any of their neighbors (in the same continent). Give the countries and continents.

SELECT name, continent FROM world x
WHERE population > ALL
	(SELECT 3*population FROM world y
		WHERE y.continent=x.continent AND x.name <> y.name);