With the development of network technology, users looking for information may send a request to various selected databases and then inspect multiple result lists. To avoid the need for inspecting multiple result lists, the database merging strategy merges the retrieval results produced by separate, autonomous servers into an effective, single ranked list. Our study deals with a particular aspect of this merging process, whereby only the rank of the retrieved records is available, and where a key points to different result lists. On the basis of this rather limited information, this paper describes the theoretical foundation and retrieval performance of our database merging approach based on logistic regression.