Data Manipulation Functions / Using Aggregate Functions

SELECT
    Continent,
    COUNT(*)
FROM country
GROUP BY Continent


Continent COUNT(*)
Asia 51
Europe 46
North America 37
Africa 58
Oceania 28
Antarctica 5
South America 14

Using COUNT(), you can determine the number of rows in a table or the number of rows that match a specific criterion. COUNT() can be used two ways: 

• Use COUNT(*) to count the number of rows in a table, whether columns contain values or NULL values

• Use COUNT(column) to count the number of rows that have values in a specific column, ignoring NULL values.