Teradata SQL has an EXPLAIN request modifier that shows the execution plan of a query.
EXPLAIN explains how a request will be processed and gives an estimate of the number of rows involved and the performance impact. Vantage supports EXPLAIN request modifiers with detailed Optimizer information, including cost estimates for Insert, Update, Upsert, Merge, and Delete steps and spool size estimates.
EXPLAIN helps you to evaluate complex queries and develop alternative, more efficient, processing strategies. You may be able to get a better plan by collecting more statistics on more columns or by defining additional indexes. Your knowledge of the demographics information may help you to identify row count estimates that seem badly wrong and help to pinpoint areas where additional statistics may help.