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MySQL - count duplicated rows
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In this article, we would like to show you how to count duplicated rows in MySQL.
Quick solution:
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SELECT 2
`column_name`, COUNT(`column_name`)3
FROM4
`table_name`5
GROUP BY 6
`column_name`7
HAVING 8
(COUNT(`column_name`) > 1);
To show how to count duplicated rows, we will use the following users table:
Note:
At the end of this article you can find database preparation SQL queries.
In this example, we will count duplicated user names.
Query:
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SELECT 2
`name`, COUNT(`name`) AS 'count'3
FROM4
`users`5
GROUP BY 6
`name`7
HAVING 8
(COUNT(`name`) > 1);Result:
create_tables.sql file:
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CREATE TABLE `users` (2
`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,3
`name` VARCHAR(100) NOT NULL,4
`email` VARCHAR(100) NOT NULL,5
`country` VARCHAR(15) NOT NULL,6
PRIMARY KEY (`id`)7
)8
ENGINE=InnoDB;insert_data.sql file:
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INSERT INTO `users`2
(`name`, `email`, `country`)3
VALUES4
('Tom', 'tom1@email.com', 'Poland'),5
('Tom', 'tom2@email.com', 'Poland'),6
('Tom', 'tom3@email.com', 'Poland'),7
('Kim', 'kim1@email.com', 'Vietnam'),8
('Kim', 'kim2@email.com', 'Vietnam'),9
('Chris', 'chris1@email.com', 'Spain'),10
('Chris', 'chris2@email.com', 'Spain'),11
('Chris', 'chris3@email.com', 'USA');