# SUM and COUNT

Language: | English • 日本語 • 中文 |
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## Contents

- 1 World Country Profile: Aggregate functions
- 2 You might want to look at these examples first
- 3 Total world population
- 4 List of continents
- 5 GDP of Africa
- 6 Count the big countries
- 7 Baltic states population
- 8 Using GROUP BY and HAVING
- 9 Counting the countries of each continent
- 10 Counting big countries in each continent
- 11 Counting big continents

### World 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.

name | continent | area | population | gdp |
---|---|---|---|---|

Afghanistan | Asia | 652230 | 25500100 | 20343000000 |

Albania | Europe | 28748 | 2831741 | 12960000000 |

Algeria | Africa | 2381741 | 37100000 | 188681000000 |

Andorra | Europe | 468 | 78115 | 3712000000 |

Angola | Africa | 1246700 | 20609294 | 100990000000 |

... |

## You might want to look at these examples first

Using SUM, Count, MAX, DISTINCT and ORDER BY.

## Total world population

Show the total **population** of the world.

world(name,continent,area,population,gdp)

```
SELECT SUM(population)
FROM world
```

```
SELECT SUM(population)
FROM world
```

## List of continents

List all the continents - just once each.

```
```

```
SELECT DISTINCT(continent)
FROM world
```

## GDP of Africa

Give the total GDP of Africa

```
```

```
SELECT SUM(gdp)
FROM world
WHERE continent = 'Africa'
```

## Count the big countries

How many countries have an **area** of at least 1000000

```
```

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

## Baltic states population

What is the total **population** of ('Estonia', 'Latvia', 'Lithuania')

```
```

```
SELECT SUM(population)
FROM world
WHERE name IN ('Estonia', 'Latvia', 'Lithuania')
```

## Using GROUP BY and HAVING

You may want to look at these examples: Using GROUP BY and HAVING.

## Counting the countries of each continent

For each **continent** show the **continent** and number of countries.

```
```

```
SELECT continent, COUNT(name)
FROM world
GROUP BY(continent)
```

## Counting big countries in each continent

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

```
```

```
SELECT continent, COUNT(name)
FROM world
WHERE population >= 10000000
GROUP BY(continent)
```

## Counting big continents

List the continents that **have** a total population of at least 100 million.

```
```

```
SELECT continent
FROM world
GROUP BY continent
HAVING SUM(population)>= 100000000
```

The nobel table can be used to practice more SUM and COUNT functions.