SQL - Add column to a table

ALTER TABLE {TABLENAME} ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL} CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE}

Add Default Value to Existing Column

-- Add default to existing column DateOfHire:

ALTER TABLE [dbo].[Employees] ADD  DEFAULT (getdate()) FOR [DateOfHire]

-- Add default value to existing column IsTerminated

ALTER TABLE [dbo].[Employees] ADD  DEFAULT ((0)) FOR [IsTerminated]

Add New Column with Default Value

-- Add new column DateOfHire with default

ALTER TABLE Employees ADD DateOfHire datetime DEFAULT (GETDATE())

-- Add new column IsTerminated with default

ALTER TABLE Employees ADD IsTerminated datetime DEFAULT (0)

Add Default Value with Create Table

CREATE TABLE [dbo].[Employees]

(

[EmployeeID] [int] IDENTITY(1,1) NOT NULL,

[FirstName] [varchar](50) NULL,

[LastName] [varchar](50) NULL,

[SSN] [varchar](9) NULL,

-- Add default of zero

[IsTerminated] [bit] NOT NULL DEFAULT ((0)) ,

-- Add default of getdate()

[DateAdded] [datetime] NULL DEFAULT (getdate()),

[Comments] [varchar](255) NULL,

[DateOfHire] [datetime] NULL

)