Query nested array by more than one condition in MongoDB

To query nested array by more than one condition in MongoDB, use the $elemMatch operator. This operator matches documents that contain an array field with at least one element that satisfies all the specified query conditions.

Syntax

db.collection.find({
    "arrayField": { 
        $elemMatch: {
            "field1": "value1",
            "field2": "value2"
        }
    }
});

Sample Data

db.demo203.insertOne({
    "_id": "101",
    "Name": "Chris",
    "details1": [
        {
            "empName": "David",
            "salary": "50000",
            "technology": [
                "MySQL",
                "MongoDB"
            ]
        },
        {
            "empName": "Carol",
            "salary": "70000",
            "technology": [
                "Java",
                "Spring"
            ]
        }
    ]
});

{ "acknowledged": true, "insertedId": "101" }

Display all documents from a collection with the help of find() method ?

db.demo203.find();

{
    "_id": "101", 
    "Name": "Chris", 
    "details1": [
        { "empName": "David", "salary": "50000", "technology": [ "MySQL", "MongoDB" ] },
        { "empName": "Carol", "salary": "70000", "technology": [ "Java", "Spring" ] } 
    ]
}

Example: Query with Multiple Conditions

Here is how to query nested array by more than one condition ?

db.demo203.find({
    details1: { 
        $elemMatch: {
            "technology": "MySQL", 
            "empName": "David"
        }
    }
}).pretty();

{
    "_id": "101",
    "Name": "Chris",
    "details1": [
        {
            "empName": "David",
            "salary": "50000",
            "technology": [
                "MySQL",
                "MongoDB"
            ]
        },
        {
            "empName": "Carol",
            "salary": "70000",
            "technology": [
                "Java",
                "Spring"
            ]
        }
    ]
}

Key Points

• $elemMatch ensures all conditions are satisfied by the same array element.
• Without $elemMatch, MongoDB would match conditions across different array elements.
• Returns the entire document when at least one array element matches all conditions.

Conclusion

Use $elemMatch to query nested arrays with multiple conditions on the same element. This ensures all conditions are evaluated against a single array element rather than across different elements.