Mongodb find in array of objects

I'm new to MongoDb, I have the same problem that Stennie describes. I tried to query this document in Compass:

    {
    "_id": 1,
    "name": {
        "first": "John",
        "last": "Backus"
    },
    "birth": {
        "$date": "1924-12-02T23:00:00.000Z"
    },
    "death": {
        "$date": "2007-03-16T23:00:00.000Z"
    },
    "contribs": ["Fortran", "ALGOL", "Backus-Naur Form", "FP"],
    "awards": [{
        "award": "National Medal",
        "year": 1975,
        "by": "NSF"
    }, {
        "award": "Turing Award",
        "year": 1977,
        "by": "ACM"
    }]
}

When to run this query:{awards: {$elemMatch: {award:'National Medal', year:1975}}} for this single document, I get the same result:

{
    "_id": 1,
    "name": {
        "first": "John",
        "last": "Backus"
    },
    "birth": {
        "$date": "1924-12-02T23:00:00.000Z"
    },
    "death": {
        "$date": "2007-03-16T23:00:00.000Z"
    },
    "contribs": ["Fortran", "ALGOL", "Backus-Naur Form", "FP"],
    "awards": [{
        "award": "National Medal",
        "year": 1975,
        "by": "NSF"
    }, {
        "award": "Turing Award",
        "year": 1977,
        "by": "ACM"
    }]
}

It is possible to obtain the single element searched for in this way:

{
    "_id": 1,
    "name": {
        "first": "John",
        "last": "Backus"
    },
    "birth": {
        "$date": "1924-12-02T23:00:00.000Z"
    },
    "death": {
        "$date": "2007-03-16T23:00:00.000Z"
    },
    "contribs": ["Fortran", "ALGOL", "Backus-Naur Form", "FP"],
    "awards": [{
        "award": "National Medal",
        "year": 1975,
        "by": "NSF"
    }, {}]

Thank you

Docs HomeMongoDB Manual

On this page

  • Query for a Document Nested in an Array
  • Specify a Query Condition on a Field in an Array of Documents
  • Specify Multiple Conditions for Array of Documents
  • Additional Query Tutorials


➤ Use the Select your language drop-down menu in the upper-right to set the language of the following examples.


The following example selects all documents where an element in the instock array matches the specified document:

Equality matches on the whole embedded/nested document require an exact match of the specified document, including the field order. For example, the following query does not match any documents in the inventory collection:

If you do not know the index position of the document nested in the array, concatenate the name of the array field, with a dot (.) and the name of the field in the nested document.

The following example selects all documents where the instock array has at least one embedded document that contains the field qty whose value is less than or equal to 20:

Using dot notation, you can specify query conditions for field in a document at a particular index or position of the array. The array uses zero-based indexing.

Note

When querying using dot notation, the field and index must be inside quotation marks.

The following example selects all documents where the instock array has as its first element a document that contains the field qty whose value is less than or equal to 20:

When specifying conditions on more than one field nested in an array of documents, you can specify the query such that either a single document meets these condition or any combination of documents (including a single document) in the array meets the conditions.

Use $elemMatch operator to specify multiple criteria on an array of embedded documents such that at least one embedded document satisfies all the specified criteria.

The following example queries for documents where the instock array has at least one embedded document that contains both the field qty equal to 5 and the field warehouse equal to A:

The following example queries for documents where the instock array has at least one embedded document that contains the field qty that is greater than 10 and less than or equal to 20:

If the compound query conditions on an array field do not use the $elemMatch operator, the query selects those documents whose array contains any combination of elements that satisfies the conditions.

For example, the following query matches documents where any document nested in the instock array has the qty field greater than 10 and any document (but not necessarily the same embedded document) in the array has the qty field less than or equal to 20:

The following example queries for documents where the instock array has at least one embedded document that contains the field qty equal to 5 and at least one embedded document (but not necessarily the same embedded document) that contains the field warehouse equal to A:

For additional query examples, see:

  • Query an Array

  • Query Documents

  • Query on Embedded/Nested Documents

How do I query an array of objects in MongoDB?

To search the array of object in MongoDB, you can use $elemMatch operator. This operator allows us to search for more than one component from an array object.

Can you have an array of objects in MongoDB?

In a MongoDB database, data is stored in collections and a collection has documents. A document has fields and values, like in a JSON. The field types include scalar types ( string , number , date , etc.) and composite types ( arrays and objects ).

How do I query multiple values in MongoDB?

MongoDB provides the find() that is used to find multiple values or documents from the collection. The find() method returns a cursor of the result set and prints all the documents. To find the multiple values, we can use the aggregation operations that are provided by MongoDB itself.

What does $IN do in MongoDB?

The $in operator selects the documents where the value of a field equals any value in the specified array. To specify an $in expression, use the following prototype: { field: { $in: [, , ... < valueN> ] } } For comparison of different BSON type values, see the specified BSON comparison order.