# Difference between revisions of "SUM and COUNT"

### 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.

bbc
name region area population gdp
Afghanistan South Asia 652225 26000000
Albania Europe 28728 3200000 6656000000
Algeria Middle East 2400000 32900000 75012000000
Andorra Europe 468 64000
...

## Exercises

Summary

Show the total population of the world.

```bbc(name, region, area, population, gdp)
```
```SELECT SUM(population)
FROM bbc
```
```SELECT SUM(population)
FROM bbc
```

List all the regions - just once each.

```SELECT DISTINCT(region)
FROM bbc
```

Give the total GDP of Africa

```SELECT SUM(gdp)
FROM bbc
WHERE region = 'Africa'
```

How many countries have an area of at least 1000000

```SELECT COUNT(name)
FROM bbc
WHERE area >= 1000000
```

What is the total population of ('France','Germany','Spain')

```SELECT SUM(population)
FROM bbc
WHERE name IN('France','Germany','Spain')
```

Using GROUP BY and HAVING.

For each region show the region and number of countries.

```SELECT region, COUNT(name)
FROM bbc
GROUP BY(region)
```

For each region show the region and number of countries with populations of at least 10 million.

```SELECT region, COUNT(name)
FROM bbc
WHERE population >= 10000000
GROUP BY(region)
```

List the regions with total populations of at least 100 million.

```SELECT region
FROM bbc
GROUP BY region
HAVING SUM(population)>= 100000000
```