RANK and DENSE_RANK difference in SQL - Step-by-Step Execution

Concept Flow - RANK and DENSE_RANK difference

Start with ordered data

↓

Apply RANK function

↓

Assign ranks with gaps for ties

↓

Apply DENSE_RANK function

↓

Assign ranks without gaps for ties

↓

Compare results

↓

End

We start with ordered data, apply RANK which assigns ranks with gaps for ties, then apply DENSE_RANK which assigns ranks without gaps, and finally compare the two results.

Execution Sample

SQL

SELECT name, score,
       RANK() OVER (ORDER BY score DESC) AS rank,
       DENSE_RANK() OVER (ORDER BY score DESC) AS dense_rank
FROM players;

This query ranks players by score using both RANK and DENSE_RANK to show the difference in handling ties.

Execution Table

Row	Name	Score	RANK() Result	DENSE_RANK() Result	Explanation
1	Alice	100	1	1	Highest score, rank 1 for both
2	Bob	90	2	2	Second highest, no tie yet
3	Charlie	90	2	2	Tie with Bob, same rank
4	David	80	4	3	After tie, RANK skips rank 3, DENSE_RANK continues sequentially
5	Eve	70	5	4	No tie, ranks continue
6	Frank	70	5	4	Tie with Eve, same rank
7	Grace	60	7	5	After tie, RANK skips rank 6, DENSE_RANK continues sequentially

💡 All rows processed, showing how RANK leaves gaps after ties, DENSE_RANK does not.

Variable Tracker

Variable	Row 1	Row 2	Row 3	Row 4	Row 5	Row 6	Row 7
RANK()	1	2	2	4	5	5	7
DENSE_RANK()	1	2	2	3	4	4	5

Key Moments - 2 Insights

Why does RANK() skip numbers after ties but DENSE_RANK() does not?

RANK() assigns the same rank to tied rows but leaves gaps in the sequence for the next rank, as seen in rows 3 and 4 in the execution_table. DENSE_RANK() assigns ranks without gaps, continuing the sequence immediately after ties.

What happens to the rank numbers when multiple rows have the same score?

Both RANK() and DENSE_RANK() assign the same rank number to all tied rows, as shown for Bob and Charlie with score 90. The difference is in how the next rank number is assigned after the tie.

Visual Quiz - 3 Questions

Look at the execution_table, what is the RANK() value for David (Row 4)?

A 3

B 2

C 4

D 5

💡 Hint

Check the RANK() Result column for Row 4 in the execution_table.

At which row does DENSE_RANK() assign rank 3?

A Row 3 (Charlie)

B Row 4 (David)

C Row 5 (Eve)

D Row 2 (Bob)

💡 Hint

Look at the DENSE_RANK() Result column in the execution_table.

If Eve's score changed to 85, how would RANK() for David change?

A It would become 5

B It would remain 4

C It would become 3

D It would become 2

💡 Hint

Consider how ranks shift when a new score is inserted between existing scores, referencing the variable_tracker.

Concept Snapshot

RANK() assigns ranks with gaps after ties.
DENSE_RANK() assigns ranks without gaps.
Both assign same rank to tied rows.
Use ORDER BY to define ranking order.
RANK() skips numbers after ties; DENSE_RANK() does not.

Full Transcript

This visual execution shows how RANK() and DENSE_RANK() assign ranks to rows ordered by score. Both functions assign the same rank to tied rows, but RANK() leaves gaps in the ranking sequence after ties, while DENSE_RANK() continues ranks sequentially without gaps. For example, Bob and Charlie tie with score 90 and both get rank 2. The next rank for David is 4 with RANK() but 3 with DENSE_RANK(). This difference is important when you want continuous ranking numbers or want to reflect gaps caused by ties.

Practice

1. What is the main difference between RANK() and DENSE_RANK() functions in SQL?

easy

A. DENSE_RANK() assigns random ranks, RANK() assigns sequential ranks.

B. RANK() skips rank numbers after ties, DENSE_RANK() does not skip numbers.

C. RANK() and DENSE_RANK() always return the same results.

D. DENSE_RANK() skips rank numbers after ties, RANK() does not skip numbers.

Solution

1. Step 1: Understand how RANK() works with ties

   RANK() assigns the same rank to tied rows but skips the next rank numbers accordingly. For example, if two rows tie for rank 1, the next rank will be 3.

2. Step 2: Understand how DENSE_RANK() works with ties

   DENSE_RANK() also assigns the same rank to tied rows but does not skip rank numbers. So after two rows tied at rank 1, the next rank will be 2.

3. Final Answer:

   RANK() skips rank numbers after ties, DENSE_RANK() does not skip numbers. -> Option B

4. Quick Check:

   Skipping ranks = RANK() [OK]

Hint: Remember: RANK skips numbers after ties, DENSE_RANK does not [OK]

Common Mistakes:

• Thinking both functions behave the same with ties
• Confusing which function skips rank numbers
• Assuming ranks are assigned randomly

2. Which of the following is the correct syntax to get the rank of employees ordered by salary using DENSE_RANK()?

easy

A. SELECT employee_id, RANK() BY salary FROM employees;

B. SELECT employee_id, DENSE_RANK(salary) FROM employees ORDER BY salary DESC;

C. SELECT employee_id, DENSE_RANK() OVER (ORDER BY salary DESC) AS rank FROM employees;

D. SELECT employee_id, DENSE_RANK() ORDER BY salary FROM employees;

Solution

1. Step 1: Identify correct DENSE_RANK() syntax

   The correct syntax uses DENSE_RANK() OVER (ORDER BY column) to rank rows based on a column.

2. Step 2: Check each option

   SELECT employee_id, DENSE_RANK() OVER (ORDER BY salary DESC) AS rank FROM employees; uses the correct window function syntax. Options A, B, and D have syntax errors or misuse the function.

3. Final Answer:

   SELECT employee_id, DENSE_RANK() OVER (ORDER BY salary DESC) AS rank FROM employees; -> Option C

4. Quick Check:

   Window function syntax = SELECT employee_id, DENSE_RANK() OVER (ORDER BY salary DESC) AS rank FROM employees; [OK]

Hint: Use OVER (ORDER BY ...) with ranking functions [OK]

Common Mistakes:

• Omitting OVER clause
• Passing column inside function parentheses
• Using wrong keywords like BY instead of ORDER BY

3. Given the table Scores with values:
Player | Score
Alice | 100
Bob | 90
Carol | 90
Dave | 80
What will be the output of this query?

SELECT Player, Score, RANK() OVER (ORDER BY Score DESC) AS Rank, DENSE_RANK() OVER (ORDER BY Score DESC) AS DenseRank FROM Scores;

medium

A. [{"Player":"Alice","Score":100,"Rank":1,"DenseRank":1},{"Player":"Bob","Score":90,"Rank":2,"DenseRank":2},{"Player":"Carol","Score":90,"Rank":2,"DenseRank":2},{"Player":"Dave","Score":80,"Rank":4,"DenseRank":3}]

B. [{"Player":"Alice","Score":100,"Rank":1,"DenseRank":1},{"Player":"Bob","Score":90,"Rank":3,"DenseRank":2},{"Player":"Carol","Score":90,"Rank":3,"DenseRank":2},{"Player":"Dave","Score":80,"Rank":4,"DenseRank":3}]

C. [{"Player":"Alice","Score":100,"Rank":1,"DenseRank":1},{"Player":"Bob","Score":90,"Rank":2,"DenseRank":3},{"Player":"Carol","Score":90,"Rank":2,"DenseRank":3},{"Player":"Dave","Score":80,"Rank":3,"DenseRank":4}]

D. [{"Player":"Alice","Score":100,"Rank":1,"DenseRank":1},{"Player":"Bob","Score":90,"Rank":2,"DenseRank":2},{"Player":"Carol","Score":90,"Rank":3,"DenseRank":2},{"Player":"Dave","Score":80,"Rank":4,"DenseRank":3}]

Solution

1. Step 1: Assign RANK() values

   Alice has highest score 100, rank 1. Bob and Carol tie at 90, both get rank 2. Because of tie at rank 2, next rank is 4 for Dave.

2. Step 2: Assign DENSE_RANK() values

   Alice is dense rank 1. Bob and Carol tie at 90, dense rank 2. Dave has next dense rank 3 (no skipping).

3. Final Answer:

   [{"Player":"Alice","Score":100,"Rank":1,"DenseRank":1},{"Player":"Bob","Score":90,"Rank":2,"DenseRank":2},{"Player":"Carol","Score":90,"Rank":2,"DenseRank":2},{"Player":"Dave","Score":80,"Rank":4,"DenseRank":3}] -> Option A

4. Quick Check:

   RANK skips numbers, DENSE_RANK does not [OK]

Hint: Check how ranks jump after ties for RANK vs DENSE_RANK [OK]

Common Mistakes:

• Assigning dense ranks with gaps
• Not skipping ranks in RANK after ties
• Mixing up rank numbers for tied rows

4. You wrote this query:

SELECT name, RANK() ORDER BY score DESC FROM players;

But it gives a syntax error. What is the problem?

medium

A. Missing OVER() clause after RANK() function.

B. ORDER BY cannot be used inside SELECT clause.

C. RANK() requires a parameter inside parentheses.

D. The table name is missing in the query.

Solution

1. Step 1: Check RANK() function usage

   RANK() is a window function and must be followed by OVER() clause specifying order.

2. Step 2: Identify missing OVER() clause

   The query uses RANK() without OVER(), causing syntax error.

3. Final Answer:

   Missing OVER() clause after RANK() function. -> Option A

4. Quick Check:

   Window functions need OVER() [OK]

Hint: Always add OVER() after window functions like RANK() [OK]

Common Mistakes:

• Forgetting OVER() clause
• Trying to put ORDER BY inside SELECT without OVER()
• Assuming RANK() takes parameters

5. You have a sales table:
Salesperson | SalesAmount
John | 500
Jane | 700
Joe | 700
Jill | 600
You want to assign ranks so that tied salespeople share the same rank and the next rank number is not skipped. Which query correctly achieves this?

hard

A. SELECT Salesperson, SalesAmount, RANK() OVER (ORDER BY SalesAmount DESC) AS Rank FROM sales;

B. SELECT Salesperson, SalesAmount, RANK() OVER (PARTITION BY SalesAmount ORDER BY SalesAmount DESC) AS Rank FROM sales;

C. SELECT Salesperson, SalesAmount, ROW_NUMBER() OVER (ORDER BY SalesAmount DESC) AS Rank FROM sales;

D. SELECT Salesperson, SalesAmount, DENSE_RANK() OVER (ORDER BY SalesAmount DESC) AS Rank FROM sales;

Solution

1. Step 1: Understand ranking requirements

   Tied salespeople should share the same rank, and the next rank number should not skip any numbers.

2. Step 2: Choose correct function

   DENSE_RANK() assigns same rank to ties and does not skip ranks. RANK() skips ranks after ties. ROW_NUMBER() never assigns same rank to ties. SELECT Salesperson, SalesAmount, RANK() OVER (PARTITION BY SalesAmount ORDER BY SalesAmount DESC) AS Rank FROM sales; misuses PARTITION BY.

3. Final Answer:

   SELECT Salesperson, SalesAmount, DENSE_RANK() OVER (ORDER BY SalesAmount DESC) AS Rank FROM sales; -> Option D

4. Quick Check:

   DENSE_RANK() for no skipped ranks after ties [OK]

Hint: Use DENSE_RANK() to avoid skipping ranks after ties [OK]

Common Mistakes:

• Using RANK() when no skipping is wanted
• Using ROW_NUMBER() which never ties
• Incorrect use of PARTITION BY in ranking