Query array of nested string with MongoDB?

To query array of nested string, you can use the dot(.) notation. Let us first create a collection with documents −

> db.nestedStringDemo.insertOne(
   {
      "CustomerName": "John",
      "CustomerOtherDetails": [ { "Age":29, "CountryName": "US" },
      { "CompanyName": "Amazon",
      "Salary": 150000, "ProjectName": ["Online Library Management System", "Pig Dice Game"]
   } ] }
);
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5cea4629ef71edecf6a1f690")
}
> db.nestedStringDemo.insertOne(
{
   "CustomerName": "Chris",
   "CustomerOtherDetails": [ { "Age":27, "CountryName": "AUS" },
   { "CompanyName": "Google",
      "Salary": 250000, "ProjectName": ["Chat Application", "Game Design"]
   } ] }
);
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5cea466eef71edecf6a1f691")
}

Following is the query to display all documents from a collection with the help of find() method −

> db.nestedStringDemo.find().pretty();

This will produce the following output −

{
   "_id" : ObjectId("5cea4629ef71edecf6a1f690"),
   "CustomerName" : "John",
   "CustomerOtherDetails" : [
      {
         "Age" : 29,
         "CountryName" : "US"
      },
      {
         "CompanyName" : "Amazon",
         "Salary" : 150000,
         "ProjectName" : [
            "Online Library Management System",
            "Pig Dice Game"
         ]
      }
   ]
}
{
   "_id" : ObjectId("5cea466eef71edecf6a1f691"),
   "CustomerName" : "Chris",
   "CustomerOtherDetails" : [
      {
         "Age" : 27,
         "CountryName" : "AUS"
      },
      {
         "CompanyName" : "Google",
         "Salary" : 250000,
         "ProjectName" : [
            "Chat Application",
            "Game Design"
         ]
      }
   ]
}

Now, let us query an array of nested string using dot notation −

> db.nestedStringDemo.find({"CustomerOtherDetails.ProjectName":"Chat Application"}).pretty();

This will produce the following output −

{
   "_id" : ObjectId("5cea466eef71edecf6a1f691"),
   "CustomerName" : "Chris",
   "CustomerOtherDetails" : [
      {
         "Age" : 27,
         "CountryName" : "AUS"
      },
      {
         "CompanyName" : "Google",
         "Salary" : 250000,
         "ProjectName" : [
            "Chat Application",
            "Game Design"
         ]
      }
   ]
}