OR-Expansion of Subqueries – Limitations
How to overcome the limitations of expansion of OR-subqueries in Oracle 19c. Continue Reading
OR-expansion
Dissecting Cost Based OR-Expansion
Analyzing the CBO trace for getting insight into the cost based OR-expansion Continue Reading
Cost-Based OR Expansion Transformation
OR expansion not working properly in Oracle 12.2 Continue Reading
Disjunctive Subquery Optimization
Disjunctive subqueries are the subqueries which are applied to the or operator. Alternatively, these queries can be rewritten to use the union all operator which may be a more efficient way to retrieve the records from the database. This blog post compares the efficiency of SQL Server and Oracle optimizer when dealing with the transformations of disjunctive subqueries.
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