Explorer
MongoDB

Skip the first 2 sensors from the `sensors` collection and return the rest.

Problem Statement

<p>Skip the first 2 <code>sensors</code> from the <code>sensors</code> collection and return the rest.</p>

Examples

Input: sensors collection: +-----+-------------+-------+ | _id | type | value | +-----+-------------+-------+ | 1 | temperature | 22.5 | | 2 | humidity | 65 | | 3 | pressure | 1013 | | 4 | temperature | 23.1 | +-----+-------------+-------+

Output: +-----+-------------+-------+ | _id | type | value | +-----+-------------+-------+ | 3 | pressure | 1013 | | 4 | temperature | 23.1 | +-----+-------------+-------+

Explanation: The query restricts and skips documents to return the specified subset.

Complexity

Time Complexity: -

Space Complexity: -

Hints

šŸ’” Hint 1: Use db.<collection>.find(<filter>) to query the documents in the collection. šŸ’” Hint 2: Pass an empty object {} to retrieve all documents, or specify key-value pairs for exact matching. šŸ’” Hint 3: Chain .toArray() to resolve the MongoDB cursor into a JavaScript array: return db.<collection>.find(...).toArray();

Editorial & Approach

Problem Overview & Intuition

To solve "Skip Results", we query the MongoDB document store. The goal is to skip the first 2 sensors from the `sensors` collection and return the rest. Using a targeted find query, the database engine filters and structures the BSON documents efficiently.

Step-by-Step Approach

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

Optimal Implementation (MongoDB)

function solve(db) {
  return db.sensors.find({}).skip(2).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.

Skip Results

Easy

Skip the first 2 sensors from the sensors collection and return the rest.

Example Scenarios
1Example 1
Input:
sensors collection
_idtypevalue
1temperature22.5
2humidity65
3pressure1013
4temperature23.1
Output:
_idtypevalue
3pressure1013
4temperature23.1
Explanation:

The query restricts and skips documents to return the specified subset.

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Query Results (JSON)

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