Quick Ref.

SELECT within SELECT

This tutorial looks at how we can use SELECT statements within SELECT statements to perform more complex queries.

Exercises

Using nested SELECT.

1a. List each country name where the population is larger than 'Russia'. 
bbc(name, region, area, population, gdp)
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1b. List the name and region of countries in the regions containing 'India', 'Iran'.

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1c. Show the countries in Europe with a per capita GDP greater than 'United Kingdom'.

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1d. Which country has a population that is more than Canada but less than Algeria?

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To get a well rounded view of the important features of SQL you should move on to the next tutorial concerning aggregates.

To gain an absurdly detailed view of one insignificant feature of the language, read on.

We can use the word ALL to allow >= or > or < or <=to act over a list.

2a. Which countries have a GDP greater than any country in Europe? [Give the name only.]

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We can refer to values in the outer SELECT within the inner SELECT. We can name the tables so that we can tell the difference between the inner and outer versions.

3a. Find the largest country in each region, show the region, the name and the population:

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The following questions are very difficult:

3b. Find each country that belongs to a region where all populations are less than 25000000. Show name, region and population.

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3c. Some countries have populations more than three times that of any of their neighbours (in the same region). Give the countries and regions.

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