Is it possible to get the datetime when only there are any data changes in the table/matrix? I don't want to always get the current datetime. I want the datetime to be refreshed only when there is a change to the data in the table/matrix.
This is only possible of you are storing a timestamp in the rows of data that are being queried. If you are storing that timestamp, then simply query it and render it outside of the tablix - you could use a Max() aggregate function to find it from the rows of data.