Many Wireless Sensor Network (WSN) applications require join of sensor data belonging to various sensor nodes. For join processing, it is important to minimize the communication cost since it is the main consumer of battery power. In this paper, they introduce a parallel join technique for sensor networks. A WSN consists of many independent sensor nodes and provides a natural platform for a shared-nothing architecture to carry out parallel processing. The proposed parallel join algorithm is based on sensor data that are stored in column-oriented databases. A column-oriented database store table data column-wise rather than row-wise as in traditional relational databases. The proposed algorithm is energy-efficient for two clear reasons.