Description

The GROUP BY clause can be used to group rows based on column values.

Let's look at a SELECT statement that uses the GROUP BY clause to group the rows.

Table Data

Before executing any queries, consider the below data on the tables.

customer_id customer_name address  city country postal_code
1 Maria Anders Obere Str. 57 Berlin Germany 12209
2 Fran Wilson C/ Araquil, 67 Madrid Spain 28023
3 Dominique Perrier 25, rue Lauriston Paris France 75016
4 Martin Blank Via Monte Bianco 34 Turin Italy 10100
5 Thomas Hardy 89 Chiaroscuro Rd. Portland USA 97219
6 Christina Aguilera Gran Va, 1 Madrid Spain 28001
7 Hanna Moos Forsterstr. 57 Mannheim Germany 68306
8 Frdrique Citeaux 24, place Klber Strasbourg France 67000
9 Laurence Lebihan 12, rue des Bouchers Marseille France 13008
10 Elizabeth Lincoln 23 Tsawassen Blvd. Tsawassen Canada T2F 8M4

SELECT With GROUP BY

The below SELECT statement groups the table rows based on the country, with a count of employees against each country.

  • We have used aliases to define custom output column names in the result set.

Run this on IDE

SELECT country AS 'Country', count(*) AS 'Number of Customers'
FROM customers
GROUP BY country;

After successful execution, the output contains the below data.

Country Number of Customers
Canada 1
France 3
Germany 2
Italy 1
Spain 2
USA 1

Overall

We now understood how to create a SELECT statement with a GROUP BY clause.

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