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Summary

Test qu2 tutorial questions

Completion information

The example shows the population of 'France'. Strings should be in 'single quotes';

Show the population of Germany

SELECT population FROM bbc
  WHERE name = 'France'

SELECT population FROM bbc
  WHERE name = 'Germany'

Completion information

This query shows the population density population/area for each country where the area is over 5,000,000 km².

Show the per capita gdp: gdp/population for each country where the area is over 5,000,000 km²

SELECT name, population/area FROM bbc
  WHERE area > 5000000

SELECT name, gdp/population FROM bbc
  WHERE area > 5000000

Completion information

Where to find some very small, very rich countries.
We use AND to ensure that two or more conditions hold true.

The example shows the countries where the population is small and the gdp is high.

Show the name and region where the area is less then 2000 and the gdp is more than 5000000000

SELECT name , region
  FROM bbc
  WHERE population < 2000000
    AND gdp > 5000000000

SELECT name , region
  FROM bbc
  WHERE area < 2000
    AND gdp > 5000000000

Completion information

Checking a list The word IN allows us to check if an item is in a list. The example shows the name and population for the countries 'Ireland', 'Iceland' and 'Denmark'

Show the name and the population for 'Denmark', 'Finland', 'Norway', 'Sweden'

SELECT name, population FROM bbc
  WHERE name IN ('Ireland', 'Iceland',
                 'Denmark')

SELECT name, population FROM bbc
  WHERE name IN ('Denmark', 'Finland',
                 'Norway', 'Sweden')

Completion information

What are the countries beginning with G? The word LIKE permits pattern matching - % is the wildcard. The examples shows countries beginning with D

Show each country that begins with G

SELECT name FROM bbc
  WHERE name LIKE 'D%'

SELECT name FROM bbc
  WHERE name LIKE 'G%'

Quiz Test

1. In a SELECT statement indicate the part that determines which rows are displayed

	CHOOSE
	GROUP BY
	ORDER BY
	HAVING
	WHERE

2. Select the statement that shows the population of 'United Kingdom'

	GIVE population OF 'United Kingdom'
	SELECT name FROM bbc WHERE population = 'United Kingdom'
	SELECT population FROM bbc WHERE name = 'United Kingdom'
	SELECT population FROM 'United Kingdom' WHERE name = 'population'
	SELECT 'United Kingdom', population FROM bbc

3. Select the statement that shows the sum of population of all countries in 'Europe'

	SELECT name, population FROM bbc WHERE region = 'Europe'
	SELECT population FROM bbc WHERE region = 'Europe' SUM BY region
	SELECT SUM(population) FROM bbc WHERE region = 'Europe'
	SELECT SUM(population FROM bbc WHERE region = 'Europe')
	SUM population FROM bbc WHERE region = 'Europe'

4. Select the statement that shows the number of countries with population smaller than 150000

	SELECT COUNT(name) FROM bbc WHERE population < 150000
	SELECT COUNT(population < 150000) FROM bbc
	SELECT name FROM bbc WHERE population < 150000
	SELECT population AS COUNT FROM bbc WHERE population < 150000
	SELECT SUM() FROM bbc WHERE population < 150000

5. Select the full set of SQL aggregate functions

	AVG(), COUNT(), FIRST(), LAST(), SUM()
	AVG(), COUNT(), MAX(), MEDIAN(), MIN(), ROUND(), SUM()
	AVG(), COUNT(), FIRST(), LAST(), MAX(), MIN(), SUM()
	AVG(), COUNT(), MAX(), MIN(), SUM()
	COUNT(), SUM()

6. Select the statement that shows the average population of 'Poland', 'Germany' and 'Denmark'

	SELECT AVG(population) FROM bbc WHERE name = ('Poland', 'Germany', 'Denmark')
	SELECT AVG(population) FROM bbc WHERE name IN ('Poland', 'Germany', 'Denmark')
	SELECT AVG(population) FROM bbc WHERE name LIKE ('Poland', 'Germany', 'Denmark')
	SELECT AVG(population) FROM bbc WHERE name LIKE (Poland, Germany, Denmark)
	SELECT population FROM bbc WHERE name IN ('Poland', 'Germany', 'Denmark')

7. Select all the statements that show all the countries in 'Africa'

	SHOW country WHERE region = 'Africa'
	SELECT country WHERE region LIKE 'Africa'
	SELECT name FROM bbc WHERE region LIKE 'Africa'
	SELECT name FROM bbc WHERE region = 'Africa'
	SELECT region = 'Africa' FROM bbc

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