7. A data processing system, comprising: a query engine; and a summary filter transformation system coupled to the query engine, wherein the summary filter transformation system is configured to: receive a query having a select list, a from element, and a summary filter having a filter condition; analyze 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; create 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; transform the received query by combining the received query with the derived table, transforming the received query comprising: traverse 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; transform the from element of the received query to reference the derived table; and add 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.
7. A data processing system, comprising: a query engine; and a summary filter transformation system coupled to the query engine, wherein the summary filter transformation system is configured to: receive a query having a select list, a from element, and a summary filter having a filter condition; analyze 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; create 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; transform the received query by combining the received query with the derived table, transforming the received query comprising: traverse 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; transform the from element of the received query to reference the derived table; and add 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. 12. The data processing system as claimed in claim 7 , wherein the summary filter transformation system is further configured to determine that the FILTER transformation can be performed, comprising: determining an aggregate group for each aggregate of the filter condition; and determining that all of the determined aggregate groups are compatible, including: determining the aggregate group with the lowest level of granularity; and determining that each aggregate group is a subset of the aggregate group with the lowest level of granularity or that each aggregate group is identical to the aggregate group with the lowest level of granularity.