Nested SELECT Quiz

Nested SELECT quiz

1. Which of these shows the name, region and population of the smallest country in each region?

	SELECT region, name, FROM bbc x WHERE population <= ALL (SELECT population FROM bbc y WHERE y.region=x.region AND population>0)
	SELECT region, name, population FROM bbc WHERE population <= ALL (SELECT population FROM bbc WHERE population>0)
	SELECT region, name, population FROM bbc x WHERE population <= ALL (SELECT population FROM bbc y WHERE y.region=x.region AND population>0)
	SELECT region, name, population FROM bbc x WHERE population = ALL (SELECT population FROM bbc y WHERE y.region=x.region AND population>0)
	SELECT region, name, population FROM bbc x WHERE population <= ALL (SELECT population FROM bbc y WHERE y.region=x.region AND population<0)

2. Which of these shows the countries belonging to regions with all populations over 50000?

	SELECT name,region,population FROM bbc x WHERE 50000 <= ALL (SELECT population FROM bbc y WHERE population>0)
	SELECT name,region,population FROM bbc x WHERE 50000 <= ALL (SELECT population FROM bbc y WHERE x.region=y.region AND y.population>0)
	SELECT name,region,population FROM bbc x WHERE 50000 = ALL (SELECT population FROM bbc y WHERE x.region=y.region AND y.population>0)
	SELECT name,region,population FROM bbc x WHERE 50000 >= ALL (SELECT population FROM bbc y WHERE x.region=y.region AND y.population>0)
	SELECT name,region,population FROM bbc x WHERE 500000 <= ALL (SELECT population FROM bbc y WHERE x.region=y.region AND y.population>0)

3. Which of these shows the countries with a third of the population of the countries around it?

	SELECT name, region FROM bbc x WHERE population < ALL (SELECT population/3 FROM bbc y WHERE y.region = x.region AND y.name != x.name)
	SELECT name, region FROM bbc x WHERE population = ALL (SELECT population/3 FROM bbc y WHERE y.region = x.region AND y.name != x.name)
	SELECT name, region FROM bbc x WHERE population > ALL (SELECT population/3 FROM bbc y WHERE y.region = x.region AND y.name != x.name)
	SELECT name, region FROM bbc x WHERE population < ALL (SELECT population*3 FROM bbc y WHERE y.region = x.region AND y.name != x.name)
	SELECT name, region FROM bbc x WHERE population < ALL (SELECT population/3 FROM bbc y WHERE y.name != x.name)

4. Which of these would show the countries with a greater GDP then any country in Africa?

	SELECT name FROM bbc WHERE gdp > ALL (SELECT MAX(gdp) FROM bbc WHERE region = 'Africa' AND gdp=0)
	SELECT name FROM bbc WHERE gdp > ALL (SELECT MAX(gdp) FROM bbc WHERE region = 'Africa' AND gdp IS NOT NULL)
	SELECT name FROM bbc WHERE gdp > ALL (SELECT MIN(gdp) FROM bbc WHERE region = 'Africa' AND gdp IS NOT NULL)
	SELECT name FROM bbc WHERE gdp > ALL (SELECT MAX(gdp) FROM bbc WHERE region = 'Africa' AND population IS NOT NULL)
	SELECT name FROM bbc WHERE gdp > ALL (SELECT MAX(gdp) FROM bbc WHERE region = 'Europe' AND gdp IS NOT NULL)

5. Which of these shows the countries with population smaller than Russia but bigger than Denmark?

	SELECT name FROM bbc WHERE population < (SELECT population FROM bbc WHERE name='Denmark') AND population > (SELECT population FROM bbc WHERE name='Russia')
	SELECT name FROM bbc WHERE population < (SELECT population FROM bbc WHERE name='Russia') AND population > (SELECT population FROM bbc WHERE name='Denmark')
	SELECT name FROM bbc WHERE population = (SELECT population FROM bbc WHERE name='Russia') AND population > (SELECT population FROM bbc WHERE name='Denmark')
	SELECT name FROM bbc WHERE population > (SELECT population FROM bbc WHERE name='Russia') AND population > (SELECT population FROM bbc WHERE name='Denmark')
	SELECT name FROM bbc WHERE population < (SELECT population FROM bbc WHERE name='Russia' AND population > (SELECT population FROM bbc WHERE name='Denmark')

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