What happens when I update SQL column to itself? -OR- simplified conditional updates?

Question

I would like to call an "update" stored procedure which won't necessarily include all columns. There is probably a better way to handle this.... As you can see, if I do not pass in the column parameters their value is NULL. Then, using the ISNULL, I set the columns either to their new values or their existing values.

CREATE PROCEDURE [dbo].[spUpdateTable] 

 @pPKID bigint = NULL,
 @pColumn1 int = NULL, 
 @pColumn2 int = NULL

AS
BEGIN

 SET NOCOUNT ON;

 UPDATE
    TableName
 SET
    [Column1] = ISNULL(@pColumn1,[Column1]),
    [Column2] = ISNULL(@pColumn2,[Column2])

 WHERE
    [PKID] = @pPKID
END

Answer 1

This is basically the same thing that the transactional replication stored procedures do when updating a table on a subscriber. If Microsoft does it themselves, it must be safe, right? :-)

Seriously, my primary concern here would be any update triggers that might exist on the table. You'd want to understand the impact of potentially firing those triggers on what could be a non-change. Otherwise I think your technique is fine.