SQL QuestSQL Interview Questions › Window Functions

RANK vs DENSE_RANK Side-by-Side

MediumFreeQuerying BasicsWindow Functions

Comp wants a teaching artifact: rank employees by performance_rating showing both RANK() and DENSE_RANK() side-by-side so the team can see what each function does when ratings tie.

Show name, performance_rating, rank_with_gaps (RANK()), and rank_no_gaps (DENSE_RANK()). Order by performance_rating descending, then name.

The difference (this is the interview answer): RANK leaves gaps after ties (1, 2, 2, 4). DENSE_RANK doesn't (1, 2, 2, 3). When the question is "who's in the top N tiers", DENSE_RANK is almost always what you want; when the question is "who's in the top N positions counting ties as taking up seats", RANK is right.

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Schema

employees

emp_idnamedepartmentpositionsalaryhire_datemanager_idperformance_rating
1Alice JohnsonEngineeringSenior Developer950002019-03-1554.5
2Bob SmithEngineeringDeveloper750002020-06-0113.8
3Carol WilliamsMarketingMarketing Manager850002018-09-20NULL4.2

Expected output: RANK = 1, 1, 3 — DENSE_RANK = 1, 1, 2

Hint

The hint for this one spells out most of the query, so it stays in the editor. Reach for SELECT, Window Functions, RANK, and open the hint there if you stall.

Concepts

SELECT Window Functions RANK DENSE_RANK

Practise the topic: SQL practice questions · Window function practice · Ranking function practice

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