Question

In Oracle12c, there is no depth limit on the number of subqueries that can be nested in a(n) FROM clause. _________________________​

A) True
B) False

Answer 1

In Oracle12c, while no specific numerical limit is documented for nested subquery depth in a FROM clause, practical limitations do exist, making the claim that there is no limit false.

Step-by-step explanation:

In Oracle12c, there is a misconception that the depth limit for subqueries nested in a FROM clause is unbounded. However, this is false. Oracle SQL has practical limitations due to system resources and parsing complexity. Although Oracle's documentation does not specify an explicit numerical limit for the depth of nested subqueries, various factors can restrict the depth in practice. For example, each additional subquery level consumes more memory and requires additional processing for parsing and execution. At a certain point, depending on the complexity of the subqueries and the resources of the database server, adding more nested subqueries could lead to performance issues or even prevent the query from executing.