Queries on software artifacts play an important role in novel software development approaches, such as Aspect-Oriented Software Development and OMG's Model Driven Architecture. Keeping them separate from the modifications operating on them has proven to be beneficial with respect to their comprehensibility and their reusability. In this paper we describe what relationships can exist between such stand-alone queries. These relationships allow the combination of existing queries to form new ones, enabling rs to come up with abstractions for common selection patterns.