oraclf 复杂查询练习_SQL复杂查询—练习(四)
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oraclf 复杂查询练习_SQL复杂查询—练习(四)
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#1.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'. select name from world where continent = 'Europe' and gdp/population > (select gdp/population from world where name = 'United Kingdom');#3.List the name and continent of countries in the continents containing either Argentina or Australia. Order by name of the country. select name,continent from world where continent in (select continent from world where name in ('Argentina','Australia')) order by name;# 4.解法一:Which country has a population that is more than Canada but less than Poland? Show the name and the population. select name,population from world where population > (select population from world where name = 'Canada') and population < (select population from world where name = 'Poland');# 4.解法二:Which country has a population that is more than Canada but less than Poland? Show the name and the population. select name,population from world where population between (select population from world where name = 'Canada')+1 and (select population from world where name = 'Poland')-1;#5.Show the name and the population of each country in Europe. Show the population as a percentage of the population of Germany. select name,concat(round((population/(select population from world where name = 'Germany'))*100,0),'%') as percentage from world where continent = 'Europe';#6.Which countries have a GDP greater than every country in Europe? [Give the name only.] (Some countries may have NULL gdp values) select name from world where gdp > all(select gdp from world where continent = 'Europe' and gdp > 0);#7.Find the largest country (by area) in each continent, show the continent, the name and the area: select continent,name,area from world as s1 where area = (select max(area) from world as s2 where s1.continent=s2.continent group by continent);#8.List each continent and the name of the country that comes first alphabetically. select continent,name from world as s1 where name <= all(select name from world as s2 where s1.continent=s2.continent group by continent);# 9.Find the continents where all countries have a population <= 25000000. Then find the names of the countries associated with these continents. Show name, continent and population.解法一: select name,continent,population from world as s1 where continent in (select continent from world as s2 where s1.continent=s2.continent group by continent having max(population) <= 25000000);解法二: select name,continent,population from world as s1 where 25000000 >= all(select population from world as s2 where s1.continent=s2.continent group by continent);#10.Some countries have populations more than three times that of any of their neighbours (in the same continent). Give the countries and continents. select name,continent from world as s1 where population/3 > all(select population from world as s2 where s1.continent=s2.continent and s1.name<>s2.name); 與50位技術專家面對面20年技術見證,附贈技術全景圖總結
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