Wireless sensor network are the collection of hundreds and thousands of tiny, battery powered sensor nodes. Sensor’s nodes co-operatively send the sense data to base station. Wireless sensor network has several applications like habitat monitoring, building monitoring, health monitoring, military surveillance and target tracking. Sensor nodes have limited energy and bandwidth. As sensor nodes are battery driven, an efficient utilization of power is essential in order to use the networks for long duration. Hence, network lifetime is most challenging task and it became necessary to reduce data traffic inside sensor networks, reduce amount of data that need to send to base station. This reduction of communication data extends the network lifetime and it is possible only if sensor nodes perform data aggregation instead of directly sending the sensed data to sink (Base station). This paper presents various data aggregation techniques in wireless sensor network and a novel Data Routing for In-network aggregation called DRINA. The main goal of data aggregation is to gather and aggregate data in energy efficient manner in order to enhance the network life time.