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MySQL - GROUP BY statement
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In this article, we would like to show you how to use GROUP BY
statement in MySQL.
Quick solution:
SELECT `column1`, `column2`, `columnN`
FROM `table_name`
WHERE condition
GROUP BY `column_name`
ORDER BY `column_name`;
Practical example
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
In this example, we will display the number of users in each country descending.
Query:
SELECT COUNT(`name`) AS `number of users`, `country`
FROM `users`
GROUP BY `country`
ORDER BY COUNT(`name`) DESC;
Output:
Database preparation
create_tables.sql
file:
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:
INSERT INTO `users`
(`name`, `country`)
VALUES
('Tom', 'Poland'),
('Chris', 'Spain'),
('Jack', 'Spain'),
('Kim', 'Vietnam'),
('Marco', 'Italy'),
('Kate', 'Spain'),
('Nam', 'Vietnam');