Hi Stephan, you're on the right track, but this is tricky in Tableau. Converting your raw start/end data into reshaped date/delta data is key. Then you can sort on date and plot a running sum of delta where delta is the number of open tickets/requests on that day. For your case I'm adding +1 to your End date so if start=end you still show that day as busy. Here's the algorithm, an image of the results, and an 8.1 packaged workbook. It uses Custom SQL with an Excel data source so won't open on Mac. It should work with both multiple and overlapping reservations. I don't know how to show the final value without showing the individual days that set up the table calculations in the first place. Putting the answer in the caption is one way to show a table calc for a view.
SELECT [Sheet1$].[Start] AS [Date],
+1 AS [Delta]
SELECT [Sheet1$].[End]+1 AS [Date],
-1 AS [Delta]
BusyBook.twbx 35.8 KB