Grouping by time from ulr source



Is there a way to create queries on data provided by URL data source? I am new to redash and i wanted to visualize some data from my REST service.

I have a service that provides access to data only via REST (it holds everything in memory). I created a proxy that maps response to format supported by redash and i can succesfully display the data as table in redash. If i want to display data like - number of rows with specific hour i have to map this in my proxy, or i can do it in redash?
Something like - each row represent event and i want to display number of events in specific hour.