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BBC Country Profile: Aggregate functions This tutorial is about aggregate functions such as COUNT,
SUM and AVG. An aggregate function takes
many values and delivers just one value. For example the function SUM
would aggregate the values 2, 4 and 5 to deliver the single value 11.
Exercises
Using SUM, COUNT,
MAX, AVG, DISTINCT and
ORDER BY.
1a. Show the total population of the world.
bbc(name , region, area, population, gdp)
Results
1b. List all the regions - just once each.
Results
1c. Give the total GDP of Africa
Results
1d. How many countries have an area of at least 1000000
Results
1e. What is the total population of ('France','Germany','Spain')
Results
Using GROUP BY and HAVING.
2a. For each region show the region and number of
countries.
Results
2b. For each region show the region and number of
countries with populations of at least 10 million.
Results
2c. List the regions with total populations of at least
100 million.
Results
The next tutorial is looks at the Table Tennis
database. It shows how queries may use records from two related
tables.