Find all employees and sort by `salary` in descending order.

Problem Statement

<p>Find all <code>employees</code> and sort by <code>salary</code> in descending order.</p>

Examples

Input: employees collection: +-----+---------+--------+ | _id | name | salary | +-----+---------+--------+ | 1 | Alice | 90000 | | 2 | Bob | 60000 | | 3 | Charlie | 120000 | +-----+---------+--------+

Output: +-----+---------+--------+ | _id | name | salary | +-----+---------+--------+ | 3 | Charlie | 120000 | | 1 | Alice | 90000 | | 2 | Bob | 60000 | +-----+---------+--------+

Explanation: The collection documents are sorted according to the specified field order.

Complexity

Time Complexity: -

Space Complexity: -

Hints

💡 Hint 1: Sort matched documents using .sort({ field: 1 }) for ascending or { field: -1 } for descending. 💡 Hint 2: Chain .sort(...) directly after db.<collection>.find(...) and before .limit() / .toArray(). 💡 Hint 3: Complete: return db.<collection>.find(<filter>).sort(<sortObj>).toArray();

Editorial & Approach

Problem Overview & Intuition

To solve "Sort Descending", we query the MongoDB document store. The goal is to find all employees and sort by `salary` in descending order. Using a targeted find query, the database engine filters and structures the BSON documents efficiently.

Step-by-Step Approach

Identify Target Collection: Access the collection through the db instance.
Construct Query / Pipeline: Build the query filter with appropriate comparison operators.
Resolve Cursor: Invoke .toArray() to transform the query cursor into the required array of documents.

Optimal Implementation (MongoDB)

function solve(db) {
  return db.employees.find({}).sort({ salary: -1 }).toArray();
}

Complexity Analysis

Time Complexity O(N) collection scan (O(log N) if index is present on filtered fields).

Space Complexity O(K) where K is the number of returned documents in memory.

Key Considerations & Edge Cases

Empty Collections: If no documents match, the query cleanly returns an empty array [].
Missing / NULL Fields: Missing fields in documents are handled safely without throwing runtime exceptions.
Type Coercion: BSON types (ObjectId, Numbers, Strings) are compared strictly according to MongoDB specifications.

Sort Descending

Easy

Find all employees and sort by salary in descending order.

Example Scenarios

1Example 1

Input:

employees collection

_id	name	salary
1	Alice	90000
2	Bob	60000
3	Charlie	120000

Output:

_id	name	salary
3	Charlie	120000
1	Alice	90000
2	Bob	60000

Explanation:

The collection documents are sorted according to the specified field order.

MongoDB Editor

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Query Results (JSON)

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