EN
MySQL - GROUP BY multiple columns
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In this article, we would like to show you how to use GROUP BY
statement with multiple columns in MySQL.
Quick solution:
SELECT `column1`, `column2`, `columnN`
FROM `table_name`
WHERE condition
GROUP BY `column1`, `column2`, `columnN`
ORDER BY `column_name`;
Practical example
To show how GROUP BY
with multiple columns works, we will use the following table:
![MySQL - example data used with GROUP BY multiple columns](/static/bucket/1618843248835-nr1AjZKA5a--image.png)
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 with the same name
and department_id
.
Query:
SELECT `name`, `department_id`, COUNT(*)
FROM `users`
GROUP BY `name`,`department_id`;
Result:
![MySQL - GROUP BY multiple columns result](/static/bucket/1618843582206-VWLD0O1YEM--image.png)
Result explanation:
As we see, the COUNT(*) column contains the number of users with the same name
and department_id
. For example, there are three people named Ailisa
in the department 3
.
Database preparation
create_tables.sql
file:
CREATE TABLE `users` (
`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
`name` VARCHAR(50) NOT NULL,
`surname` VARCHAR(50) NOT NULL,
`department_id` INT(10) UNSIGNED,
`salary` DECIMAL(15,2) NOT NULL,
PRIMARY KEY (`id`)
);
insert_data.sql
file:
INSERT INTO `users`
( `name`, `surname`, `department_id`, `salary`)
VALUES
('John', 'Stewart', 1, '2000.00'),
('Chris', 'Brown', 3, '2000.00'),
('Chris', 'Lewis', 3, '2000.00'),
('Kate', 'Lewis', 3, '2000.00'),
('Kate', 'Stewart', 3, '2000.00'),
('Ailisa', 'Lewis', 3, '2000.00'),
('Ailisa', 'Gomez', 3, '3000.00'),
('Gwendolyn', 'James', 2, '3000.00'),
('Simon', 'James', 2, '2000.00'),
('Simon', 'Brown', 3, '2000.00'),
('Simon', 'Collins', 3, '3000.00');