In an information retrieval system, a query optimization method transforms maximum or minimum function aggregation predicates on a non-indexed column into a single sort function. The method evaluates the query to identify a table and a predicate equating a column of the table to a sub-query that applies...http://www.google.se/patents/US7542962?utm_source=gb-gplus-sharePatent US7542962 - Information retrieval method for optimizing queries having maximum or minimum function aggregation predicates
