The issue of data quality is gaining importance as individuals as well as corporations are increasingly relying on multiple, often external sources of data to make decisions. Traditional query systems do not factor in data quality considerations in their response. Studies into the diverse interpretations of data quality indicate that fitness for use is a fundamental criteria in the evaluation of data quality. In this paper, we present a 4 step methodology that includes user preferences for data quality in the response of queries from multiple sources. User preferences are modelled using the notion of preference hierarchies. We have developed an SQL extension to facilitate the specification of preference hierarchies. Further, we will demonstrate through experimentation how our approach produces an improved result in query response.