Add an new Triggered Action selector
It would be nice to have the ability to run a Triggered Action on only a single field being Updated. In this case I have a table which has a field which can contain the ID number for another user. This field might start out blank and can later be edited. None of the current selectors (less than, blank, exists, etc..) can accommodate a random value that you don't have any idea in advance what it might be. Might it be possible to have "Changed, or Unchanged" meaning compare the new value to the old value or lack of and then run the Triggered Action.
Tony S commented
it can be achieved by combining (using JOIN) two tables - your_table and #inserted for the On-Update event, and put your_table.user_id not equal #inserted.user_id in WHERE section. This gives you access to an old and a new value even.
So the action will be run only if that field (user_id) is changed if you will attach such kind of JOIN to it