The various joins described in the previous sections demonstrate some of the different ways in which a SQL statement can be written. We even provided an example showing how the same query could be written using two different formats. The job of the optimizer is to take the SQL statement and determine the most efficient (we hope) manner in which to process the query.

This section continues the background discussion by presenting some of the more common ways in which Oracle processes a query. The term access path is used for the manner in which Oracle identifies the rows to be retrieved and retrieves them.