What are Window Functions?

What are Window Functions?

Window functions compute aggregated values across related partitions of rows while retaining the original row-level granularity (they do not collapse rows like GROUP BY).

Key Syntax Structure

SELECT 
    name, department, salary,
    AVG(salary) OVER(PARTITION BY department) AS dept_avg,
    DENSE_RANK() OVER(PARTITION BY department ORDER BY salary DESC) AS rank
FROM employees;

Ranking Functions Comparison