1. A method, in a data processing system having a processor, of summary filter query transformation, the method comprising: receiving, in a summary filter transformation system of the data processing system, a query having a select list, a from element, and a summary filter having a filter condition; analyzing, by an analysis module of the summary filter transformation system, the filter condition to determine a filter group of the filter condition, the filter group comprising a list of expressions over which the filter condition is computed; creating, by the analysis module, a derived table for computing the filter condition, the derived table having a select list, creating the derived table comprising: adding the list of expressions of the filter group to the derived table as one or more columns of the derived table's select list; and adding the filter condition to the derived table as a one or more columns of the derived table's select list; transforming, by a transformation module of the summary filter transformation system, the received query by combining the received query with the derived table, transforming the received query comprising: traversing the select list of the received query and transforming one or more aggregates of the select list to reference one or more of the columns of the derived table; transforming the from element of the received query to reference the derived table; and adding a WHERE clause to the transformed original query, the WHERE clause based on the filter condition and referencing one or more of the columns of the derived table.