You may not be familiar with the term subquery factoring. Prior to the release of Oracle 11gR2, the official Oracle documentation barely mentions it, providing just a brief synopsis of its use, a couple of restrictions, and a single example. If I instead refer to the WITH clause of the SELECT statement, you probably know immediately what I mean, because these terms are more recognizable. Both terms are used in this chapter.
In Oracle 11gR2 (version 11.2), the WITH clause was enhanced with the ability to recurse; that is, the factored subquery is allowed to call itself within some limitation. The value of this may ...