Compare ROW_NUMBER, RANK, and DENSE_RANK for Top-k Results

# Compare ROW_NUMBER, RANK, and DENSE_RANK for Top-k Results Explain how ROW_NUMBER, RANK, and DENSE_RANK differ when selecting top results within a group. Discuss both tied and untied values and explain which interpretation of “top three” each function can support. This is a conceptual ranking question; no concrete table or SQL output contract is supplied. ### What a Strong Answer Covers - Unique sequential row numbers versus tied ranks with and without gaps. - A distinction between exactly three rows, the first three competition ranks, and the best three distinct values. - Ordering and tie-breaker requirements that preserve the intended meaning of ties. ```hint Use four scores with a tie Compare the ranks assigned to scores 100, 90, 90, and 80 in descending order. ``` ### Follow-up Questions - Why can adding a unique identifier to every window order remove intended ties? - What changes when a group contains fewer than three rows?