What does the following query do? SELECT id, salary, ROW_NUMBER() OVER (PARTITION BY dept ORDER BY salary DESC) AS rn FROM employees QUALIFY rn = 1

Question

SQL Fundamentals — Hard

What does the following query do? SELECT id, salary, ROW_NUMBER() OVER (PARTITION BY dept ORDER BY salary DESC) AS rn FROM employees QUALIFY rn = 1

Accepted Answer

The query returns the highest-paid employee per department by using the ROW_NUMBER() window function to assign a ranking based on salary within each department. The QUALIFY clause filters the results to only include employees with a ranking of 1, effectively selecting the top earner in each department.