I have a data set that includes PO numbers. Some PO's may have been shipped against multiple times meaning they have the same number, but different delivery dates. I need to find the average # days a PO was in-transit but rather than by PO, by each PO's delivery date. When I try and do a box and whisker plot in Tableau, it will calculate the # days based on the average of all the records it has for that one PO. I want it to plot the same PO multiple times based upon each delivery date. Any thoughts about how to do this?