Nth Highest Salary Query That Actually Performs #SQL #DatabaseTuning #Tutorial

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 R…