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Query transformation for queries involving correlated subqueries having correlation join predicates with local filtering predicates involving predicate transitive closure and predicate pull-out
Query transformation for queries involving correlated subqueries having correlation join predicates with local filtering predicates involving predicate transitive closure and predicate pull-out
A method, apparatus, and article of manufacture for optimizing a query in a computer system, wherein the query is performed by the computer system to retrieve data from a database stored on the computer system. The optimization is performed by identifying a correlated subquery in the query that qualifies for transformation, transitively closing a local filtering predicate within the identified correlated subquery that is on a same column as a correlation join predicate within the identified correlated subquery, and pulling out or bubbling up the transitively closed predicate from the correlated subquery to a parent query block of the query.
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