How to Change a Column to Allow NULL in SQL ServerSee SQL Server: Tips and Tricks for similar articles.
If you have a column in a SQL Server table that does not allow NULL values and you need to change it to allow NULLs, here is how you do it.
Let's say, you created a table like this:
CREATE TABLE Employees ( EmployeeID int IDENTITY(1,1) PRIMARY KEY, FirstName NVARCHAR(25) NOT NULL, LastName NVARCHAR(25) NOT NULL );
Then you hire Madonna and realize you need to make
LastName nullable. Here's how you change it.
ALTER TABLE Employees ALTER COLUMN LastName NVARCHAR(25) NULL;