This Sum is not really stored somewhere. However, you can calculate the same in a microflow and store it wherever you want. Depending on the data you are showing in the Grid and the filter options you have, there is multiple ways to do so.
- If you allow your user to filter the grid (Also if you don’t), you could just add a button to the grid that triggers a microflow, with a List of objects as input (This will by default get the entire list of objects from the grid). Now you can have an aggregate List action that is taking the sum and storing it somewhere.
- If you don’t allow users to filter, you could just have a Microflow (Datasource Microflow of a Dataview or whatever) that is executing the same Xpath as your grid and then do the aggregation and store it somewhere.