Wireless sensor network is an application specific network. There are various factors which affects reliability in Wireless Sensor Network some of them are energy consumption, high packet loss, congestion and large response time. There are different parameters, which affects query response time. Whenever Sink [Base Station] needs data, it sends query to source node and node response back to sink. In Wireless Sensor Networks (WSNs) query response time depends on number of parameters like data caching, routing algorithm, node deployment, topology, data availability, query aggregation, query processing, packet loss and congestion. This paper presents a survey of various approaches which help us to minimize query response time mainly for wireless sensor networks.