A New Approach For Calculating Average Value (including null) Without Aggregate Function

Abstract

An evaluation of aggregate functions in relational database system considerable impact on performance in many application areas like geographic information systems and statistical and scientific databases. The problem with existing systems is inefficient execution of aggregate functions with large data volumes and lack of flexibility. It is not possible to extend the systems with new aggregate (average) functions. We show how this could be implemented into a database. We also describe how support for special kinds of aggregate queries and data structures can help in designing future high performance systems.