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MySQL - GROUP BY statement

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Created by:

illona

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In this article, we would like to show you how to use GROUP BY statement in MySQL.

Quick solution:

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SELECT `column1`, `column2`, `columnN`
FROM `table_name`
WHERE condition
GROUP BY `column_name`
ORDER BY `column_name`;

Practical example

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To show how the GROUP BY statement works, we will use the following table:

Note:

At the end of this article you can find database preparation SQL queries.

Example

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In this example, we will display the number of users in each country descending.

Query:

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SELECT COUNT(`name`) AS `number of users`, `country`
FROM `users`
GROUP BY `country`
ORDER BY COUNT(`name`) DESC;

Output:

Database preparation

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create_tables.sql file:

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CREATE TABLE `users` (
    `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
    `name` VARCHAR(100) NOT NULL,
    `country` VARCHAR(15) NOT NULL,
    PRIMARY KEY (`id`)
)
ENGINE=InnoDB;

insert_data.sql file:

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INSERT INTO `users`
    (`name`, `country`)
VALUES
    ('Tom', 'Poland'),
    ('Chris', 'Spain'),
    ('Jack', 'Spain'),
   ('Kim', 'Vietnam'),
   ('Marco', 'Italy'),
    ('Kate', 'Spain'),
    ('Nam', 'Vietnam');