Codestin Search App

Nth Highest Salary - Problem

Database Medium

You're working with a company's Employee database that contains salary information. Your task is to find the n^th highest distinct salary from the Employee table.

The Employee table structure:

Column Name	Type
id	int
salary	int

Important points:

id is the primary key with unique values
You need to find distinct salaries (duplicates don't count)
If there are fewer than n distinct salaries, return null
The ranking is from highest to lowest (1st highest, 2nd highest, etc.)

Example: If salaries are [100, 200, 300, 200], the distinct salaries in order are [300, 200, 100]. So the 2nd highest distinct salary is 200.

Input & Output

example_1.sql — Basic Case

$ Input: Employee table: [{"id": 1, "salary": 100}, {"id": 2, "salary": 200}, {"id": 3, "salary": 300}], n = 2

› Output: 200

💡 Note: The distinct salaries in descending order are [300, 200, 100]. The 2nd highest distinct salary is 200.

example_2.sql — With Duplicates

$ Input: Employee table: [{"id": 1, "salary": 100}, {"id": 2, "salary": 200}, {"id": 3, "salary": 300}, {"id": 4, "salary": 200}], n = 2

› Output: 200

💡 Note: The distinct salaries are [300, 200, 100]. Even though 200 appears twice, it's still the 2nd highest distinct salary.

example_3.sql — Not Enough Salaries

$ Input: Employee table: [{"id": 1, "salary": 100}], n = 2

› Output: null

💡 Note: There is only 1 distinct salary (100), but we need the 2nd highest. Since there aren't enough distinct salaries, we return null.

Constraints

The Employee table contains at least 0 rows
1 ≤ n ≤ 500
salary values can be any integer
Return null if there are fewer than n distinct salaries
id values are unique (primary key constraint)

Visualization

Tap to expand

Understanding the Visualization

Gather All Scores

Collect all employee salaries from the database table

Apply DENSE_RANK()

Assign consecutive ranks to distinct salary values, handling ties appropriately

Filter by Position

Find all salaries that have exactly the nth rank

Return Result

Return the salary value or null if the position doesn't exist

Key Takeaway

🎯 Key Insight: DENSE_RANK() is the perfect tool for finding nth distinct highest values because it automatically handles duplicates while maintaining consecutive ranking, exactly matching our requirement for distinct salary positions.

Asked in

G Google 85 a Amazon 72 ⊞ Microsoft 68 f Meta 45 Apple 35 O Oracle 92

The optimal solution uses the DENSE_RANK() window function to efficiently rank salaries in descending order. This approach automatically handles duplicate salaries by assigning them the same rank while maintaining consecutive ranking for distinct values. The query filters results where the rank equals n, returning the nth highest distinct salary or null if insufficient distinct salaries exist. Time complexity is O(n log n) with database optimizations.

Common Approaches

Approach	Time	Space	Notes
✓ Brute Force (Nested Subqueries)	O(n²)	O(1)	Count distinct salaries greater than each salary to find ranking
DISTINCT + ORDER BY + LIMIT	O(n log n)	O(n)	Remove duplicates, sort salaries, then pick the nth one
DENSE_RANK() Window Function (Optimal)	O(n log n)	O(n)	Use DENSE_RANK() to efficiently handle duplicates and get exact ranking

Brute Force (Nested Subqueries) — Algorithm Steps

For each salary in the table, count distinct salaries greater than it
Find the salary where exactly (n-1) distinct salaries are higher
Return null if no such salary exists

Visualization

Tap to expand

Step-by-Step Walkthrough

Select First Salary

Pick a salary from the table

Count Higher Salaries

Count how many distinct salaries are greater

Check if nth Position

If count equals n-1, this is our answer

Repeat for All

Repeat process for every salary in table

Code -

solution.c — C

#include <stdio.h>
#include <stdlib.h>

void getNthHighestSalary(int n) {
    printf("SELECT DISTINCT salary "
           "FROM Employee e1 "
           "WHERE (SELECT COUNT(DISTINCT salary) "
           "       FROM Employee e2 "
           "       WHERE e2.salary > e1.salary) = %d", n-1);
}

int main() {
    int n;
    scanf("%d", &n);
    getNthHighestSalary(n);
    return 0;
}

Time & Space Complexity

Time Complexity

⏱️

O(n²)

For each of n salaries, we count distinct higher salaries requiring another scan

⚠ Quadratic Growth

Space Complexity

O(1)

No additional space needed beyond the query execution

✓ Linear Space

89.4K Views

Very High Frequency

~15 min Avg. Time

2.8K Likes

Ln 1, Col 1

Smart Actions

💡 Explanation

AI Ready

💡 Suggestion Tab to accept Esc to dismiss

// Output will appear here after running code

Code Editor Closed

Click the red button to reopen

Input & Output

Constraints

Visualization

Related Problems

Common Approaches

Brute Force (Nested Subqueries) — Algorithm Steps

Visualization

Code -

Time & Space Complexity

Select Compiler