Enhanced rough SQL for correlated subqueries

We discuss some enhancements of approximate SQL extensions available in Infobright's database technology. We explain how these new enhancements can speed up execution of complex correlated sub-queries, which are quite popular in advanced database applications. We compare our research to the state-of-the-art solutions in the area of analytic databases. We also show in what sense our technology follows the principles of rough sets and granular computing.