Wireless sensor networks composed of battery-powered sensor nodes are invaluable instruments for remote environment sensing. For sensor network applications, sensed readings are often collected in the form of aggregated data from a portion of a sensor network as requested by spatial aggregation queries. In a large distributed sensor network, queries can be issued from various locations at any time. Existing in-network query execution techniques execute queries independently that considerably overconsumes the precious energy of sensor nodes. As a result, the lifespan of a sensor network is inevitably shortened. In this paper, we propose a Materialized In-Network View (MINV) framework that precalculates aggregated data from clusters of sensor nodes as intermediate query results preserved in the network and made ready for queries. The executions of queries are performed as simple collections of these aggregated data. Thus, the quantities and sizes of messages transmitted among sensor nodes can be greatly reduced, thus prolonging the lifetime of a sensor network. Through extensive simulations, the effectiveness of our proposed framework is validated.