Help Altering Database Table from NULL to NOT NULL

I would drop and add the table but the data can't be deleted. So if anyone could help with the statement it would be greatly appreciated. ThanksYou alter columns to NOT NULL, not tables. Can you explain why you're trying to do this? What are you going to put in all the columns that have NULL? Why does the table have NULL in the first place. You should post what the table looks like with a couple sample rows.|||My apologies I meant a column. Currently a remote table that I'm adding a new column to where the people there have no idea how to use SQL Server. I've made a new SQL script to add a new column and have to set the column to NULL since its a new column being added to an existing table. After the apropriate data is in the new column I need to set the column to NOT NULL for future entries.....|||Could you add the column allowed to have NULL, then update the table where the column get's some value, then alter the table setting the column to NOT NULL?|||Thats pretty much what I'm trying to do but via scripts. Circumstances keep me from doing this manually so I'm trying to get it setup via a script.....|||so at which of the three steps are you stuck?|||Are you just trying to change the column null to not null if something is meet?|||if exists (select 1 from your_table where new_column is null)
raiserror ('You can't make column NON-NULLABLE if there is at least 1 NULL in it!, 15, 1)
else
alter table your_table alter column new_column <data_type> not null