MySQL Alter Table Add Column First - SQL

Introduction

In MySQL, the ALTER TABLE statement is used to modify the structure of an existing table. One of the modifications you can make with the ALTER TABLE statement is adding a new column to a table.

The ADD COLUMN clause is used to add a new column to an existing table. By default, MySQL will add the new column to the end of the table. However, you may want the new column to appear at the beginning of the table. In this case, you can use the FIRST keyword to specify the position of the new column.

In this guide, we will discuss how to add a new column to the beginning of a MySQL table using the ADD COLUMN clause with the FIRST keyword.

Syntax

The syntax for adding a new column to a MySQL table with the FIRST keyword is as follows:

ALTER TABLE table_name
ADD COLUMN new_column_name column_definition FIRST;

Here, table_name is the name of the table to which you want to add the new column, new_column_name is the name of the new column, column_definition is the datatype and any other settings for the new column, and FIRST specifies that the new column should appear at the beginning of the table.

Example

Let's say we have a table called customers with the following columns:

CREATE TABLE customers (
  id INT AUTO_INCREMENT PRIMARY KEY,
  first_name VARCHAR(50),
  last_name VARCHAR(50),
  email VARCHAR(50),
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

Now, we want to add a new column called phone_number at the beginning of the table. To do this, we can use the following SQL statement:

ALTER TABLE customers
ADD COLUMN phone_number VARCHAR(20) FIRST;

After running this statement, the customers table will have the following columns:

id, phone_number, first_name, last_name, email, created_at

Note that the new column phone_number appears at the beginning of the table, before the existing columns.

Conclusion

Adding a new column to a MySQL table with the FIRST keyword is a simple way to control the position of the new column in the table. By using the ADD COLUMN clause with the FIRST keyword, you can easily insert a new column at the beginning of the table, rather than at the end.