$setIsSubset

The $setIsSubset operator in Amazon DocumentDB is used to determine if a set of values is a subset of another set. It is useful for performing set-based comparisons and operations on array fields.

Parameters

Example (MongoDB Shell)

The following example demonstrates the usage of the $setIsSubset operator to check if the tags field is a subset of the specified set.

Create sample documents

db.products.insertMany([
  { _id: 1, name: "Product A", tags: ["tag1", "tag2", "tag3"] },
  { _id: 2, name: "Product B", tags: ["tag1", "tag2"] },
  { _id: 3, name: "Product C", tags: ["tag2", "tag3"] }
]);

Query example

db.products.find({
  $expr: { $setIsSubset: [["tag1", "tag2"], "$tags"] }
})

*Note:* $setIsSubset is an aggregation operator and cannot be used directly in find() queries. In this example, $expr is used with find() to bridge the gap between query operators and aggregation expressions.

Output

[
  { "_id" : 1, "name" : "Product A", "tags" : [ "tag1", "tag2", "tag3" ] },
  { "_id" : 2, "name" : "Product B", "tags" : [ "tag1", "tag2" ] }
]

The query returns the documents where the tags field is a subset of the set ["tag1", "tag2"].

Code examples

To view a code example for using the $setIsSubset command, choose the tab for the language that you want to use:

Node.js

const { MongoClient } = require('mongodb');

async function example() {
  const client = await MongoClient.connect('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false');
  const db = client.db('test');
  const collection = db.collection('products');

  const result = await collection.find({
    $expr: { $setIsSubset: [["tag1", "tag2"], "$tags"] }
  }).toArray();

  console.log(result);

  await client.close();
}

example();

Python

from pymongo import MongoClient

def example():
    client = MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false')
    db = client['test']
    collection = db['products']

    result = list(collection.find({
        '$expr': {'$setIsSubset': [['tag1', 'tag2'], '$tags']}
    }))

    print(result)

    client.close()

example()