题目链接:https://sqlzoo.net/wiki/SELECT_from_WORLD_Tutorial

1
select name,continent,population from world

2
select name from world
where population > 200000000

3
select name,gdp/population from world where population > 200000000

4
select name,population/1000000 from world where continent = 'South America'

5
select name,population from world where name in ('France','Germany','Italy')

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select name from world where name like '%United%'

7
select name,population,area from world
where area > 3000000 or population > 250000000

8
select name,population,area from world
where (area > 3000000 and population <250000000)
or (area < 3000000 and population >250000000)

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select name,round(population/1000000,2),round(gdp/1000000000,2)
from world where continent = 'South America'

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select name,round(gdp/population,-3) from world where gdp>1000000000000

11
SELECT name,capital FROM world
WHERE LENGTH(name)=LENGTH(capital)

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SELECT name, capital FROM world
where left(name,1)= left(capital,1) and name<>capital

13
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 '% %'