Add a column, with a default value, to an existing table in SQL Server

Syntax

 ALTER TABLE {TABLENAME}   
 ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL}   
 CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE}  
 [WITH VALUES]  

Example

 ALTER TABLE table  
 ADD column BIT   
 CONSTRAINT Constraint_name DEFAULT 0 WITH VALUES  

Note : WITH VALUES handles the NOT NULL part...