database - Performance comparison of WITH clause and inner queries? -


i want know of clause , inner queries more expensive , lead more response time. of these 2 lead better performance?

using "likely" give better performance, if you're using same multiple times in select. can use /*+ materialize */ optimizer materialize subquery once.

that been said, dependent on query itself. @ times, optimizer might decide unnest subquery: subquery unnesting optimization converts subquery join. in such case, if appropriate, 'materializing' (as above) prevent it!


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