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https://sqlzoo.net/wiki/SELECT_within_SELECT_Tutorial

SELECT within SELECT Tutorial - SQLZOO

SELECT within select tutorial

--no1

select name from world
where population > (select population from world
where name='Russia')

 

--no2

select name
from world
where continent='Europe' and (gdp/population) >
(select gdp/population from world
where name='United Kingdom')

--no3

select name, continent
from world
where
continent = (select continent from world where name='Argentina')
or
continent = (select continent from world where name='Australia')
order by name;

SELECT name, continent
FROM world
WHERE continent IN (SELECT continent FROM world WHERE name IN ('Argentina', 'Australia'))
ORDER BY name

--no4

select name, population from world
where
population >
(select population from world where name = 'Canada')
and
population <
(select population from world where name = 'Poland')

--no5

select name, concat(ROUND((population/
(select population from world where name = 'Germany'))*100,0),'%')
as Percentage
from world where continent = 'Europe';

 

--no6

select name from world
where
gdp > all
(select gdp from world where gdp > 0 and continent='Europe');

--no7

SELECT continent, name, area
FROM world x
WHERE area >= ALL
(SELECT area FROM world y WHERE y.continent=x.continent AND area>0)

--no8

SELECT continent, name
FROM world x
WHERE name <= ALL(SELECT name FROM world y WHERE y.continent = x.continent)

--no9

select
name, continent, population
from world x
where 25000000 >=
all(select population from world y
where x.continent = y.continent and population > 0)

--no10

SELECT name, continent
FROM world x
WHERE population > 
ALL(SELECT population*3 FROM world y 
WHERE x.continent = y.continent AND population > 0 AND y.name != x.name)