As far as I understand, given a query, Oracle tries different approaches based on some heuristics, where I guess the most driving factor is minimizing the number of rows to work with, and then chooses the best one based on that and other factors. When you write EXPLAIN PLAN, it gives you the finally chosen plan.

As far as I understand, given a query, Oracle tries different approaches based on some heuristics, where I guess the most driving factor is minimizing the number of rows to work with, and then chooses the best one based on that and other factors. When you write EXPLAIN PLAN, it gives you the finally choosen plan.