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;