In order to achieve this I believe you would need to concatenate multiple rows into a single line. As you can imagine, that could get quite complex if you are not sure of the maximum number of students you could have in one grade (obviously that is asking for the sky!).
anyway.... in the attached file, I have managed to display multiple rows into a single line and then showed that on the Tool Tip, but when you look at the code behind, you will see that I have written up a CASE statement to try and build that statement.
I have not seen or used 'loop' commands in Tableau. Anyone aware of these?
This is where previous_value comes in - see my attached workbook at the bottom of the thread I posted.
Our threads crossed on your previous reply. Interesting suggestion to use previous_value. Let me rejig my solution...