Aggregate field on a basic model table

I’d reccomend you look into rollup summary fields within standard salesforce capabilities.  (But these are only available for Master Detail relationships… ) 

Otherwize I don’t think there is going to be a declarative solution. 

Hi Rob, thanks for the response. I’m familiar with roll up summary fields in salesforce (the quantity owned field above is one). The problem is I need a sum of reservations to show how many items are available within a given date range defined by another custom object. Perhaps I should give more background on what I’m trying to do. Equipment groups are checked in and out for a show. When someone wants to book a new show, they go to reserve their items. They need to be able to see which equipment is going to be available during their specific date range. I was building this natively in salesforce with an apex trigger but I felt Skuid would be a better interface for my users. Does this make sense?