SUM and COUNT -- SQLZOO

SUM and COUNT

SUM and COUNT -- SQLZOO

注意:where语句中对表示条件的需要用单引号, 下面的译文使用的是有道翻译如有不正确,请直接投诉有道

 01.Show the total population of the world.

译文:展示世界总人口。

SELECT SUM(population) FROM world

02.List all the continents - just once each.

译文:列出所有的大陆——每个大陆只列出一次。

SELECT DISTINCT continent FROM world

03.Give the total GDP of Africa

译文:看看非洲的GDP总量

SELECT SUM(gdp) FROM world WHERE continent = ‘Africa‘

04.How many countries have an area of at least 1000000

译文:有多少国家的面积至少有100万。

SELECT COUNT(name) FROM world WHERE area >= 1000000

05.What is the total population of (‘Estonia‘, ‘Latvia‘, ‘Lithuania‘)

译文:爱沙尼亚、拉脱维亚、立陶宛的总人口是多少?

SELECT SUM(population) FROM world WHERE name IN (‘Estonia‘, ‘Latvia‘, ‘Lithuania‘)

06.For each continent show the continent and number of countries.

译文:表示每个洲的洲数和国家数。

SELECT continent, COUNT(name) FROM world GROUP BY continent

07.For each continent show the continent and number of countries with populations of at least 10 million.

译文:每一洲显示人口至少为1 000万的洲和国家数目。

SELECT continent, COUNT(name) FROM world WHERE population > 10000000 GROUP BY continent

08.List the continents that have a total population of at least 100 million.

译文:列出总人口至少为1亿的大洲。

SELECT continent FROM world GROUP BY continent HAVING SUM(population) >= 100000000

 

练习网址:https://sqlzoo.net/wiki/SUM_and_COUNT

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SUM and COUNT -- SQLZOO

SUM and COUNT -- SQLZOO

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