A method is provided for converting a single database query into multiple database queries for multiple databases and aggregating the results of each of the queries. The method includes receiving, from a calling device, an input database query including a selection set defining an aggregation key, at least one first field to be queried in a first database, and at least one second field to be queried in a second database, generating a first database query representing a first request to retrieve the at least one first field from the first database, generating a second database query representing a second request to retrieve the at least one second field from the second database, aggregating the first response and a second response to the second database query from the first database to produce an aggregated response, and providing the aggregated response to the calling device.