Execution strategies for SQL subqueries
Mostafa Elhemali, César A. Galindo-Legaria, Torsten Grabs, Milind M. Joshi · 2007
Optimizing SQL subqueries has been an active area in database research and the database industry throughout the last decades. Previous work has already identified some approaches to efficiently execute relational subqueries. For satisfactory performance, proper choice of subquery execution strategies becomes even more essential today with the increase in decision support systems and automatically generated SQL, e.g., with ad-hoc reporting tools. This goes hand in hand with increasing query complexity and growing data volumes, which all pose challenges for an industrial-strength query optimizer.