Key TakeAways

Syntax

DEFAULT (column_name)...

How to Add DEFAULT CONSTRAINT

To add a DEFAULT constraint to a MySQL table, there are two methods available....

Using DEFAULT Constraint on CREATE TABLE

We can add a DEFAULT constraint while creating a table in MySQL....

Add DEFAULT Constraint with ALTER TABLE Statement

We can add DEFAULT Constraint to a already existing table using ALTER TABLE Statement....

DEFAULT Constraint Example

Let’s create a MySQL table “blog_posts”...

Key TakeAways:

Compatibility with Data Types: The default value must be compatible with the column’s data type. Expression Defaults (MySQL 8.0.13+): Starting from MySQL 8.0.13, you can use expressions as default values. Limitations on BLOB and TEXT Columns: Prior to MySQL 8.0.13, BLOB and TEXT columns cannot have a DEFAULT value due to their nature of storing large amounts of data. However, from MySQL 8.0.13 and onward, this restriction has been lifted for certain expressions like CURRENT_TIMESTAMP. NOT NULL Columns: If a column is set to NOT NULL without a DEFAULT value explicitly defined, and you try to insert a row without specifying a value for this column, MySQL will throw an error. Defining a DEFAULT value can prevent such errors....