mysql----Nested SELECT Quiz

Nested SELECT quiz

1. Select the code that 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. Select the code that 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. Select the code that shows the countries with a less than 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. Select the result that would be obtained from the following code:

SELECT name FROM bbc
 WHERE population >
       (SELECT population
          FROM bbc
         WHERE name=‘United Kingdom‘)
   AND region IN
       (SELECT region
          FROM bbc
         WHERE name = ‘United Kingdom‘)

5. Select the code that would show the countries with a greater GDP than any country in Africa (some countries may have NULL gdp values).

SELECT name FROM bbc
 WHERE gdp > ALL (SELECT MAX(gdp) FROM bbc WHERE region = ‘Africa‘ AND gdp=0)

SELECT name FROM bbc
 WHERE gdp > (SELECT MAX(gdp) FROM bbc WHERE region = ‘Africa‘)

SELECT name FROM bbc
 WHERE gdp > ALL (SELECT MIN(gdp) FROM bbc WHERE region = ‘Africa‘)

SELECT name FROM bbc
 WHERE gdp > ALL (SELECT gdp FROM bbc WHERE region = ‘Africa‘)

SELECT name FROM bbc
 WHERE gdp > ALL (SELECT gdp FROM bbc WHERE region = ‘Africa‘ AND gdp<>NULL)

6. Select the code that 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‘)

7. >Select the result that would be obtained from the following code:

SELECT name FROM bbc
 WHERE population > ALL
       (SELECT MAX(population)
          FROM bbc
         WHERE region = ‘Europe‘)
   AND region = ‘South Asia‘