Executing correlated and multi-row subqueries in a MPP database

The invention enables a correlated or multi-row subquery (CSQ) to be performed on distributed MPP and shared-nothing databases by broadcasting intermediate results, prior to a correlation operation, from subquery execution on one segment to all other segments in the distributed database so that the respective CSQs of each segment will have access to the necessary results to permit correct execution of the CSQ. Additionally, the intermediate results are saved to disk to avoid the necessity of replicating the same intermediate results multiple times during execution of a subquery plan.