The contribution of our approach is that we develop a framework for processing and answering queries flexibly by applying data mining techniques. In addition, we suggest strategies to reduce the computational complexity of the advanced query answer generation process. We believe that our approach enhances user-machine interfaces significantly to conventional databases with additional features. This chapter is structured as follows. The next section introduces motivating examples to show the advantages of advanced query processing. Following that we survey related works on intelligent query processing. Then we present our approach to process different types of queries using data mining techniques. The final section discusses our conclusions and possible extensions of our work for future research.