To my understanding, single value uses the first value of the result table.
However, how do I build the search for the single value panel to show the total and sparkline underneath to show average?
Also, how do I change the trend indicator to compare current total and total an hour ago?
I'm trying to achieve something very similar (without the trend part). I can show the total using addcoltotals, however, then the sparkline is messed up. Then, when I have a nice sparkline, then the total is nowhere to be shown... Did you come to a solution on this matter?
If you'd like to see the total as the "main" single value, you'll have to forfeit the use of timechart (since this will be time-based), which will then forfeit the sparkline and trend indicator. I think you best bet may be to separate this into two different single value visualizations. One single value visualization for the running total, and a separate one where you show the 15 min average, which will can include the trend from an hour ago.