ROW_NUMBER, RANK and DENSE_RANK

Ranking Functions

Example

SELECT name, marks,
  ROW_NUMBER() OVER (ORDER BY marks DESC) AS rn,
  RANK()       OVER (ORDER BY marks DESC) AS rnk,
  DENSE_RANK() OVER (ORDER BY marks DESC) AS drnk
FROM students;

Summary

• ROW_NUMBER = always unique; RANK = skips after ties; DENSE_RANK = no skip.
• Great for "top N" and leaderboard queries.

Ranking Functions

Example

SELECT name, marks,
  ROW_NUMBER() OVER (ORDER BY marks DESC) AS rn,
  RANK()       OVER (ORDER BY marks DESC) AS rnk,
  DENSE_RANK() OVER (ORDER BY marks DESC) AS drnk
FROM students;

सारांश

• ROW_NUMBER = हमेशा unique; RANK = ties के बाद skip; DENSE_RANK = no skip।
• "top N" और leaderboard queries के लिए बढ़िया।