Has anyone successfully used a variable in the length parameter of VARCHAR? I need to append a comment to a long field that often already has a string in it. I'm checking the length of the field, then I want to append my comment to the end. Below is what I'd like to do, but it only works if I use a literal in place of @LEN in the SET COMMENTS statement:

DECLARE @ADD1 AS VARCHAR(15)
DECLARE @LEN AS INT
SET @ADD1 = 'This...