EXECUTING A QUERY HAVING MULTIPLE SET OPERATORS

摘要

According to an example, a method for executing a query having multiple set operators includes adding an additional column that associates an identifier of the result table with data contained in the input result table in each input result table of an input query. The method also includes performing a Union All operation on the data contained in the input result tables to generate an intermediate result set, performing a Group By operation on the data contained in the intermediate result set to generate a grouped result set, wherein the Group By operation operates on various groups of rows and returns one row per each of the various groups, adding aggregation columns in the grouped result set containing counts of a number of times that each tuple exists in each of the input result tables, and applying a predicate on the grouped result set to execute the query.