Modifying null column to not null

Question

How to make a NULLABLE column to NOT NULL in SQL SERVER. I made a table with four columns:

My table:

id int null
fname varchar not null
last name not null
contact int null.

Now what i am required is to make id column to be not null.So please help me how we can make a null column to be a not null column.

Answer 1

Use the following statements to do it. Change the name of column id as required

UPDATE [Table] SET id=0 WHERE id IS NULL;
ALTER TABLE [Table] ALTER COLUMN id INTEGER NOT NULL;

Replace [Table] with the name of the table

Answer 2

first Update id Column '0'(Zero) where NULL then right Click on table then select Design and uncheck Allow Nulls checkbox of your Column from sql table design.

Answer 3

ALTER TABLE tableName

ALTER COLUMN columnName nvarchar(200) [NULL|NOT NULL]