System and method of query transformation

摘要

A mechanism is provided for transforming an original database query into a supported database query that can be fully computed by a target database. The original database query comprising a select list including a plurality of expressions, the plurality of expressions having a control break. The plurality of expressions includes an expression that cannot be directly computed by the target database. The mechanism constructs a derived table from the unsupported database query comprising constructing a new select list of the derived table, traversing the plurality of expressions of the select list of the unsupported database query, and adding a GROUP BY expression to the derived table based on the new select list of the derived table. The mechanism constructs the supported database query using the unsupported database query and the derived table.