The use of hints in SQL-nested query optimization
The query optimization phase in query processing plays a crucial role in choosing the most efficient strategy for executing a query. In this paper, we study an optimization technique for SQL-Nested queries using Hints. Hints are additional comments that are inserted into an SQL statement for the purpose of instructing the optimizer to perform the specified operations. We utilize various Hints including Optimizer Hints, Table join and anti-join Hints, and Access method Hints. We analyse the performance of various nested queries using the TRACE and TKPROF utilities which provide query execution statistics and execution plans. (c) 2007 Elsevier Inc. All rights reserved.
hints sql nested query query optimization trace tkprof