Oracle Database 12c SQL Programming

Most people solve the Nth highest salary problem using DENSE_RANK. It works… but it doesn’t scale. In this video, we break down a real Oracle SQL scenario with 1 million rows where 90% of the data has the same salary. This kind of skewed dataset is very common in real-world systems, and it exposes the difference between writing a correct query and writing an efficient one. First, we look at the standard “fresher” approach using DENSE_RANK and understand why it forces Oracle to scan and process all rows. Then we move to the “senior” approach, where we use a descending index, DISTINCT, and ROWNUM to fetch only the required data. The result is the same, but the performance difference is massive. If you want to improve your SQL performance and start thinking like an experienced developer, this is something you should not ignore. ------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog: Previous Tutorial ► ============================= ►►►Camera Gears https://www.amazon.in/shop/manishsharma?listId=DU9UM0XL97KM&ref=idea_share_inf ►►► Work From Home Essential Tech That We Use Daily https://www.amazon.in/shop/manishsharma?listId=XAZ18JLLSNB5&ref=idea_share_inf ============================= ============================= Subscribe now for more database tutorials ============================= @RebellionRider ============================= ►►►Connect With Us ============================= https://www.instagram.com/RebellionRider/ https://www.facebook.com/TheRebellionRider/ https://twitter.com/RebellionRider https://www.linkedin.com/in/mannbhardwaj/ ============================= ►►►Books I refer to ============================= PL/SQL https://amzn.to/2QE1jX0 Performance Tuning https://amzn.to/2sgiAw4 1z0-071 Exam https://amzn.to/2sgfeJw Python Programming https://amzn.to/305UEbh ============================= ►►►AFFILIATE DISCLOSURE: ============================= Some of the links used in the description will direct you to Amazon.in. As an Amazon Associate, I earn from qualifying purchases at no additional cost to you. #RebellionRider