SQL Server – How to alter column nvarchar length without drop

I’m trying to alter the length of the column “Body” in table “Post” like this:

ALTER TABLE Post ALTER COLUMN Body nvarchar(8000) NOT NULL;

The column is defined as nvarchar(4000) and it gives me this error:

Msg 2717, Level 16, State 2, Line 1 The size (8000) given to the parameter ‘Body’ exceeds the maximum allowed (4000).

Answer

Use Max instead. If the column were declared as VARCHAR, 8000 would be ok.

ALTER TABLE Post ALTER COLUMN Body nvarchar(max) NOT NULL;