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Subquery Factoring (WITH) Clause (Doc ID 1662498.1)

Last updated on JUNE 13, 2023

Applies to:

Oracle Database - Enterprise Edition - Version and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.


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If similar subqueries appear more than once in a sql, it is worth trying to rewrite the query using WITH subquery.
There are some things we should consider in order to get the benefit from it.


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In this Document
 Subquery Factoring
 Things to Consider when Deciding to Use Subquery Factoring
 Examples of Subquery Factoring
 Influencing the Plan with Hints and Parameters
 Optimizer Parameter
 Query 1 - Without Subquery Factoring
 Query 1 - With Subquery Factoring
 Query 2 - Without Subquery Factoring
 Query 2 - With Subquery Factoring

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