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MySQL - add column to existing table
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In this article, we would like to show you how to add a column to an existing table in MySQL.
Quick solution:
ALTER TABLE `table_name`
ADD `column_name` DATA_TYPE;
Note:
Go to the official documentation to see what you can use as
DATA_TYPE.
To add columns to an existing table we use ALTER TABLE statement.
Practical examples
To show how to add a column to an existing table using ALTER TABLE statement, we will use the following table:
Note:
At the end of this article you can find database preparation SQL queries.
ALTER TABLE - ADD COLUMN
In this example, we will add email column to the users table.
Query:
ALTER TABLE `users`
ADD `email` VARCHAR(255);
Output (SELECT * FROM `users`):
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, '3512.00'),
('Chris', 'Brown', 2, '1344.00'),
('Kate', 'Lewis', 3, '6574.00'),
('Ailisa', 'Gomez', NULL, '6500.00'),
('Gwendolyn', 'James', 2, '4200.00'),
('Simon', 'Collins', 4, '3320.00'),
('Taylor', 'Martin', 2, '1500.00'),
('Andrew', 'Thompson', NULL, '2100.00');