题目链接:https://sqlzoo.net/wiki/SELECT_from_WORLD_Tutorial
select name,continent,population from world
select name from world
where population > 200000000
select name,gdp/population from world where population > 200000000
select name,population/1000000 from world where continent = 'South America'
select name,population from world where name in ('France','Germany','Italy')
select name from world where name like '%United%'
select name,population,area from world
where area > 3000000 or population > 250000000
select name,population,area from world
where (area > 3000000 and population <250000000)
or (area < 3000000 and population >250000000)
select name,round(population/1000000,2),round(gdp/1000000000,2)
from world where continent = 'South America'
select name,round(gdp/population,-3) from world where gdp>1000000000000
SELECT name,capital FROM world
WHERE LENGTH(name)=LENGTH(capital)
SELECT name, capital FROM world
where left(name,1)= left(capital,1) and name<>capital
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 '% %'