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

Adding a Column with Default Value in SQL

When extending an existing MySQL database, it may become necessary to add a new column with a predefined default value. To address this, this article will provide a comprehensive guide on the syntax required for such an operation.

Syntax

ALTER TABLE table_name ADD COLUMN column_name data_type DEFAULT default_value;

For instance, to add a column named "score" to a table named "scores" with a default value of 0, the following command can be used:

ALTER TABLE scores ADD COLUMN score INT DEFAULT 0;

Breakdown of the Syntax

• ALTER TABLE: Indicates the start of the command to modify the existing table.
• table_name: Specifies the name of the table where the column will be added.
• ADD COLUMN: Introduces the new column to be added.
• column_name: Specifies the name of the new column.
• data_type: Defines the type of data that the new column will hold (e.g., INT, VARCHAR, etc.).
• DEFAULT default_value: Sets the default value for the column being added.

Note: It's crucial to ensure that the specified default value is compatible with the data type of the column. For instance, for an INT column, the default value should be an integer.

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