sqlzoo练习系列(六)——子查询之SELECT中的SELECT练习
【Tips】
- sqlzoo官网链接:
- 每个系列开头介绍所用表及其信息
- 每道题均测试通过,含有题目描述、代码和结果
- 题目为自己简写,最好在官网查看具体题目
- 部分测试结果不完整,仅为一部分截图
SELECT中的SELECT练习链接:
- name:国家名称
- continent:洲
- area:面积
- population:人口
- gdp:国内生产总值
SELECT name FROM world WHERE population > (SELECT population FROM world WHERE name='Russia')
SELECT name FROM world WHERE continent='Europe' AND gdp/population>(SELECT gdp/population FROM world WHERE name='United Kingdom')
SELECT name,continent FROM world WHERE continent IN (SELECT continent FROM world WHERE name='Argentina' OR name='Australia') ORDER BY name
SELECT name,population FROM world WHERE population > (SELECT population FROM world WHERE name='Canada') AND population < (SELECT population FROM world WHERE name='Poland')
SELECT name,CONCAT(ROUND(population/ (SELECT population FROM world WHERE name = 'Germany') *100,0),'%') FROM world WHERE continent = 'Europe'
SELECT name FROM world WHERE population >= ALL(SELECT population FROM world WHERE population>0) -- population>0,保证某些人口是没有填入,只有 null值。
SELECT name FROM world WHERE gdp > ALL (SELECT gdp FROM world WHERE continent = 'Europe' AND gdp>0)
SELECT continent,name,area FROM world x WHERE area >= ALL (SELECT area FROM world y WHERE x.continent=y.continent AND area>0)
SELECT continent,name FROM world x WHERE name <=ALL(SELECT name FROM world y WHERE x.continent = y.continent)
SELECT name,continent,population FROM world x WHERE 25000000>=ALL(SELECT population FROM world y WHERE x.continent = y.continent AND population>0)
SELECT name,continent FROM world x WHERE population/3 >= ALL(SELECT population FROM world y WHERE x.continent = y.continent AND population>0 AND x.name != y.name)