When you start creating tables and setting them so they can’t have NULL values, you’ll eventually need a way to define a default value for the column. A default value is one that a column would apply to its record if a value is not provided.
To specify the default value in a SQL statement, assign the desired value to the DEFAULT keyword. Here are examples:
CREATE TABLE character ( firstName NVARCHAR(50) , lastName NVARCHAR(50) , Planet NVARCHAR(20) DEFAULT N'Tatooine' )
When in doubt, start on Tatooine!
You don’t have to use literal values for DEFAULT. You could use a function too.
CREATE TABLE character ( firstName NVARCHAR(50) , lastName NVARCHAR(50) , Planet NVARCHAR(20) DEFAULT N'Tatooine' , birthDate DATETIME DEFAULT GETDATE() )
If the table exists already and you want to add a column that has a default value, use the ALTER TABLE command.
ALTER TABLE &let;TableName> ADD &let;ColumnName> DEFAULT &let;value>
Let’s assume the birthDate column hadn’t already been added to the character table.
ALTER TABLE character ADD COLUMN birthDate DATETIME DEFAULT GETDATE()
That’s all you have to remember in order to set a column to use a DEFAULT value. If you have any questions, send ’em in. I’m here to help!