How to set a default value for an existing column

This will work in SQL Server:

ALTER TABLE Employee ADD CONSTRAINT DF_SomeName DEFAULT N'SANDNES' FOR CityBorn;

The correct way to do this is as follows:

1. Run the command:

   sp_help [table name] 
   

2. Copy the name of the CONSTRAINT.

3. Drop the DEFAULT CONSTRAINT:

   ALTER TABLE [table name] DROP [NAME OF CONSTRAINT] 
   

4. Run the command below:

   ALTER TABLE [table name] ADD DEFAULT [DEFAULT VALUE] FOR [NAME OF COLUMN]
   

cannot use alter column for that, use add instead

ALTER TABLE Employee 
ADD DEFAULT('SANDNES') FOR CityBorn

ALTER TABLE Employee ADD DEFAULT 'SANDNES' FOR CityBorn