This paper describes the technologies developed for the extraction and publication of large volumes of statistical information, such as are produced by public data collection organisations and National Statistical Institutes (NSIs); the approach has been implemented in the MISSION system that has been developed as part of a EU Fifth Framework project. We review the MISSION system, and then focus on our novel approach that utilises metadata to simplify the user interface and database query process, by allowing the user to browse metadata to compose a query by specifying the format of the answer. The system then decomposes the request into query fragments, works out what type of data could be used to answer these query fragments, and searches the metadata to find where such data can be found and what processing is required. Once the query has been composed, data and metadata are retrieved from the distributed sites, processed, combined appropriately and the result returned to the user.