sqlzoo答案4：SELECT within SELECT Tutorial

sql练习：SELECT within SELECT Tutorial - SQLZoo

world表：

name	continent	area	population	gdp
Afghanistan	Asia	652230	25500100	20343000000
Albania	Europe	28748	2831741	12960000000
Algeria	Africa	2381741	37100000	188681000000
Andorra	Europe	468	78115	3712000000
Angola	Africa	1246700	20609294	100990000000
...

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

1. select...where...(...select...)

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')

2.

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

Per Capita GDP?

The per capita GDP is the gdp/population

Europe是在continent里面筛选，不是area

select name 
from world 
where continent = 'Europe' 
and gdp/population >
(select gdp/po