How to Add a New Column with a Default Value in MySQL?

Adding a New Column with a Default Value in SQL

When expanding a database schema, it's often necessary to add new columns. In MySQL, this can be achieved using the ALTER TABLE statement. One essential consideration is assigning an appropriate default value to the new column to maintain data integrity.

Syntax:

To add a column with a default value of 0 to a MySQL table named 'table1', use the following syntax:

ALTER TABLE table1 ADD COLUMN foo INT DEFAULT 0;

Explanation:

• The ALTER TABLE statement modifies the existing table 'table1'.
• The ADD COLUMN clause creates a new column named 'foo' of the INT (integer) data type.
• The DEFAULT 0 clause assigns a default value of 0 to the 'foo' column, meaning that new rows inserted into the table will receive this value if it's not explicitly specified.

Reference:

The MySQL documentation provides extensive information on modifying tables using ALTER TABLE, including the addition of new columns with default values. Refer to the following sections:

• [ALTER TABLE Syntax](https://dev.mysql.com/doc/refman/8.0/en/alter-table.html)
• [CREATE TABLE Syntax](https://dev.mysql.com/doc/refman/8.0/en/create-table.html)

By understanding the syntax and referencing the official documentation, you can effortlessly add new columns with default values to your MySQL databases, ensuring data integrity and simplifying data manipulation processes.

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