Query MongoDB subdocument to print on one line?

To display subdocuments in one line format, use $unwind along with aggregate() to flatten array elements, then iterate through results with a custom function.

Syntax

db.collection.aggregate([
    { $match: { "field": "value" } },
    { $unwind: "$arrayField" }
]).forEach(function(doc) {
    print(doc.field1 + ", " + doc.arrayField.subfield + ", " + doc.arrayField.subfield2);
});

Sample Data

db.demo183.insertOne({
    "_id": "110",
    "DueDate": ISODate("2020-02-04T01:10:42.000Z"),
    "ProductDetails": [
        {
            "ProductName": "Product-1",
            "isAvailable": true
        },
        {
            "ProductName": "Product-2",
            "isAvailable": false
        }
    ]
});

{ "acknowledged": true, "insertedId": "110" }

Example: Query Subdocuments in One Line

Create a custom function to format output and use $unwind to flatten the array ?

var productdata = function (d) {
    print(d.DueDate + ", " + d.ProductDetails.ProductName + ", " + d.ProductDetails.isAvailable);
}

var iterator = db.demo183.aggregate([
    { $match: { _id: "110" } },
    { $unwind: '$ProductDetails' }
]);

iterator.forEach(productdata);

Tue Feb 04 2020 06:40:42 GMT+0530 (India Standard Time), Product-1, true
Tue Feb 04 2020 06:40:42 GMT+0530 (India Standard Time), Product-2, false

How It Works

• $unwind creates separate documents for each array element
• $match filters documents by specific criteria
• forEach() iterates through results and applies custom formatting function
• Each subdocument is printed on a single line with comma-separated values

Conclusion

Use $unwind in aggregation pipeline to flatten subdocument arrays, then apply forEach() with a custom function to display each subdocument on one formatted line.