Patent ID: 7542962
Filing Date: 2009-06-02
Classification: G06F,Y10S

Abstract:
1. A method for optimizing a query, comprising: evaluating the query to identify an aggregation predicate that contains an aggregation sub-query wherein the aggregation sub-query equates to-a selected column of a table wherein the aggregation sub-query applies an aggregation function to the selected column to return an aggregate value for the selected column, the aggregate value for selecting at least one row from the table to produce a query result, the aggregation function comprising one of a minimum function and a maximum function; determining whether an index exists for the selected column of the table; and reforming the query in response to determining that an index does not exist for the selected column by replacing the aggregation sub-query with the aggregation function such that the selected column is effectively equated to the aggregation function wherein the reformed query is executed by a single pass of the table by storing a first temporary result that satisfies the aggregation function and replacing the first temporary result with a second temporary result in response to determining that a second temporary result satisfies the aggregation function in relation to the first temporary result.