Advanced Ranking with DENSE_RANK, RANK, and NTILE

SELECT
    student_name,
    score,
    RANK() OVER (ORDER BY score DESC) as rank_score,
    DENSE_RANK() OVER (ORDER BY score DESC) as dense_rank_score,
    NTILE(4) OVER (ORDER BY score DESC) as quartile
FROM student_scores
ORDER BY score DESC;

How it works: This snippet showcases different SQL ranking window functions. `RANK()` assigns a unique rank, but skips numbers for ties (e.g., 1, 2, 2, 4). `DENSE_RANK()` assigns consecutive ranks even with ties (e.g., 1, 2, 2, 3), making it useful for leaderboards where ties should still occupy a 'slot'. `NTILE(N)` divides the ordered set into N groups (e.g., quartiles for N=4), assigning a group number to each row, valuable for percentile-based analysis.