ORACLE SQL ROWNUM execution order

Question

in Oracle SQL, there is a possible rownum criterion. Can I confirm that rownum will be executed as soon as the limit for the number of records is returned? or can it be executed first, before other WHERE SQL criteria (let if we put rownum in front of others)?

Answer 1

This is not the equivalent of LIMIT in other languages. If you plan to limit the number of records using rownum, you need to query ORDER BY internally and use rownum in the outer query. The order of the elements in your WHERE clause does not matter. See this great article from Tom Kyte.

Answer 2

, WHERE ROWNUM , .

GROUP BY ORDER BY.