Count how many orders have `status: "delivered"` AND `total` greater than `200`.

Problem Statement

<p>Count how many <code>orders</code> have <code>status: "delivered"</code> AND <code>total</code> greater than <code>200</code>.</p>

Examples

Input: orders collection: +-----+-----------+-------+ | _id | status | total | +-----+-----------+-------+ | 1 | delivered | 300 | | 2 | pending | 500 | | 3 | delivered | 100 | | 4 | delivered | 250 | +-----+-----------+-------+

Output: +-------+ | count | +-------+ | 2 | +-------+

Explanation: The query calculates the total count of documents that satisfy the given filter criteria.

Complexity

Time Complexity: -

Space Complexity: -

Hints

💡 Hint 1: Use comparison operators ($gt, $gte, $lt, $lte) to filter documents based on numeric or date ranges. 💡 Hint 2: Construct the filter condition: { fieldName: { $gt: value } } inside db.<collection>.find(...). 💡 Hint 3: Chain projection or sorting if requested, and invoke .toArray() to produce the result array.

Editorial & Approach

Problem Overview & Intuition

To solve "Filter + Count Documents", we query the MongoDB document store. The goal is to count how many orders have `status: "delivered"` and `total` greater than `200`. 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.orders.countDocuments({ status: "delivered", total: { $gt: 200 } });
}

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.

Filter + Count Documents

Easy

Count how many orders have status: "delivered" AND total greater than 200.

Example Scenarios

1Example 1

Input:

orders collection

_id	status	total
1	delivered	300
2	pending	500
3	delivered	100
4	delivered	250

Output:

count
2

Explanation:

The query calculates the total count of documents that satisfy the given filter criteria.

MongoDB Editor

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Query Results (JSON)

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