IS WITH clause more efficient?

Does using with clause improve performance?

Oracle call's the WITH clause "sub-query factoring". Its main use is to improve the performance of queries which use the same sub-query more than once. We can also use it to make our code easier to understand but over-simplification can cause poor performance.

What is the advantage of WITH clause in SQL?

The WITH clause was introduced in SQL:1999 to define views that are only valid for the query they belong to. Also known as common table expressions (CTEs), WITH clauses allow us to improve the structure of an SQL statement without polluting the database namespace. As you can see, we can have multiple CTEs in one query.

Why with clause is faster in Oracle?

The answer as usual is DEPENDS on WHAT YOU ARE COMPARING with. If the WITH clause is used to do something that would otherwise need PL/SQL then it will be better than PL/SQL. The optimizer decides execution plan. And at times have no performance penalty, but at other times it may do something more complex.

Why do we use with clause?

WITH clause allows us to give a subquery block a name that can be used in multiple places within the main SELECT, INSERT, DELETE or UPDATE SQL query. The name assigned to the subquery is treated as though it was an inline view or a table. It is very helpful when you need the same set of results data multiple times.