Check out the topic Programming Tiggers in the BOL. Basically you have two options: IF UPDATED() and IF COLUMNS_UPDATED(). IF UPDATED() uses the column name while IF COLUMNS_UPDATED() works off of a bitmask.
IF UPDATED('lastName')
BEGIN
...
END
-Mike
>Suppose I have a row in a table where the lastname field is 'Jones'.
>
>Now suppose I do an UPDATE on that row, and set the lastname to 'Jones'
>
>
>Is there anything I can check in the update trigger that will tell me whether one of the columns that I updated was the lastname column, even though the value itself didn't change?
>
>(It may sound like a silly question, but the answer is important to an authentication method that we're considering).
>
>Thanks,
>Kevin
