sqlzoo:SELECT from WORLD Tutorial

╰+攻爆jí腚メ 2022-12-20 08:54 91阅读 0赞

> 1.  show the name, continent and population of all countries.

SELECT name, continent, population FROM world

> 1.  Show the name for the countries that have a population of at least 200 million.

SELECT name FROM world
    WHERE population>200000000

> 1.  Give the name and the per capita GDP for those countries with a population of at least 200 million.

SELECT name, gdp/population
    FROM world
    WHERE population>200000000

> 1.  Show the name and population in millions for the countries of the continent ‘South America’.

SELECT name, population/1000000
    FROM world
    WHERE continent='South America'

> 1.  Show the name and population for France, Germany, Italy

SELECT name, population
    FROM world
    WHERE name
      IN ('France', 'Germany', 'Italy')

> 1.  Show the countries which have a name that includes the word ‘United’

SELECT name
    FROM world
    WHERE name
      LIKE '%United%'

> 1.  Show the countries that are big by area or big by population. Show name, population and area.

SELECT name, population, area
    FROM world
    WHERE population>250000000
      OR area>3000000

> 1.  Show the countries that are big by area (more than 3 million) or big by population (more than 250 million) but not both. Show name, population and area.

SELECT name, population, area
    FROM world
    WHERE population>250000000
      XOR area>3000000

> 1.  For South America show population in millions and GDP in billions both to 2 decimal places.

SELECT name, ROUND(population/1000000, 2), ROUND(gdp/1000000000, 2)
    FROM world
    WHERE continent='South America'

> 1.  Show per-capita GDP for the trillion dollar countries to the nearest $1000.

SELECT name, ROUND(gdp/population/1000, 0)*1000
    FROM world
    WHERE gdp>1000000000000

> 1.  Show the name and capital where the name and the capital have the same number of characters.

SELECT name, capital
    FROM world
    WHERE LENGTH(name)=LENGTH(capital)

> 1.  Show the name and the capital where the first letters of each match. Don’t include countries where the name and the capital are the same word.

SELECT name, capital
    FROM world
    where name<>capital 
      AND LEFT(name, 1)=LEFT(capital, 1)

> 1.  Find the country that has all the vowels and no spaces in its name.

SELECT name
    FROM world
    WHERE name LIKE '%a%'
      AND name LIKE '%e%'
      AND name LIKE '%i%'
      AND name LIKE '%o%'
      AND name LIKE '%u%'
      AND name NOT LIKE '% %'