The View Matching algorithm determines whether materialized views can be used to satisfy a query. This determination takes place in two steps: a query evaluation step, and a materialized view evaluation step.
The optimizer includes a materialized view in the set of materialized views to be examined by the View Matching algorithm if the view definition:
contains only one query block
contains only one FROM clause
does not contain any of the following constructs or specifications:
The materialized view definition may contain a GROUP BY clause, and a HAVING clause, provided the HAVING clause does not contain subselects or subqueries.
These restrictions only apply to the materialized views that are considered by the View Matching algorithm. If a materialized view is explicitly referenced in a query, the view is used by the optimizer as if it was a base table.
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