Systems and methods for intelligent capture and fast transformations of granulated data summaries in database engines

Embodiments may provide methods and systems for intelligent capture and fast transformation of granulated data summaries. An engine may be used to transform input data summaries into result sets representing query outcomes. The data summaries contain enough knowledge about the original data to accurately perform operations on the summaries without needing to access the original data. In an embodiment, the contents of data summaries are accessible via an SQL approximate engine which retrieves summaries stored on disk and utilizes them for its operations. Alternatively, the contents of data summaries are accessible via virtual tables which give users direct access to the summary contents and allow for the creation and implementation of algorithms to work with the data summaries independently from the SQL approximate engine.