You can use $avg operator along with aggregate framework. Let us first create a collection with documents −> db.averageOfRatingsInArrayDemo.insertOne( ...   { ...      "StudentDetails":[ ...         { ...             "StudentId":1, ...             "StudentScore":45 ...         }, ...         { ...           "StudentId":2, ...           "StudentScore":58 ...         }, ...         { ...           "StudentId":3, ...     ... Read More

You can use $or operator along with limit(1) to match element in array. Let us first create a collection with documents −> db.matchElementInArrayDemo.insertOne( ...   { ...      "StudentName" : "Chris" , ...      "StudentOtherDetails" : ...      [ ...         {"StudentCountryName" : "US" , "StudentSkills" : "MongoDB"}, ...         {"StudentCountryName" : "UK" , "StudentSkills" : "Java"} ...       ] ...   } ... ); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd423282cba06f46efe9ee2") } > db.matchElementInArrayDemo.insertOne( ...   { ...      "StudentName" : "Chris" , ...   ... Read More

To get specific object from array of objects, use positional operator($). Let us first create a collection with documents −> db.getASpecificObjectDemo.insertOne( ...   { ...      _id :1, f ...      "CustomerName" : "Larry", ...      "CustomerDetails" : { ...         "CustomerPurchaseDescription": [{ ...            id :100, ...            "ProductName" : "Product-1", ...            "Amount":10000 ...         }, { ...               id :101, ...               "ProductName" : ... Read More

You can use aggregate framework for this. Let us first create a collection with documents −> db.summingSubDocumentDemo.insertOne( ... { "_id" :101, "CustomerDetails" : { "CustomerPurchase" : { "CustomerPurchaseAmount" : 2000 } } }); { "acknowledged" : true, "insertedId" : 101 } > db.summingSubDocumentDemo.insertOne( { "_id" :102, "CustomerDetails" : { "CustomerPurchase" : { "CustomerPurchaseAmount" : 3000 } } }); { "acknowledged" : true, "insertedId" : 102 } > db.summingSubDocumentDemo.insertOne( { "_id" :103, "CustomerDetails" : { "CustomerPurchase" : { "CustomerPurchaseAmount" : 5000 } } }); { "acknowledged" : true, "insertedId" : 103 }Following is the query to display all documents ... Read More

To retrieve multiple items in an array, use aggregate framework. Let us first create a collection with documents −> db.retrieveMultipleDemo.insertOne( ...   { ...      "UserDetails": ...      [ ...         { "_id": "101", "UserName":"John", "UserAge": 23 }, ...         { "_id": "102", "UserName":"Carol", "UserAge": 21 }, ...         { "_id": "103", "UserName":"David", "UserAge": 23}, ...         { "_id": "104", "UserName":"Sam", "UserAge": 25} ...      ] ...   } ... ); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd40c85edc6604c74817cf0") }Following is the query to ... Read More

You can use aggregate framework for this. Here, we will get the sum and then match it to search for documents less than a particular number. Let us first create a collection with documents −> db.searchDocumentsDemo.insertOne({"Value1":100, "Value2":560}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd3fe1eedc6604c74817ce9") } > db.searchDocumentsDemo.insertOne({"Value1":300, "Value2":150}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd3fe29edc6604c74817cea") } > db.searchDocumentsDemo.insertOne({"Value1":400, "Value2":200}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd3fe30edc6604c74817ceb") } > db.searchDocumentsDemo.insertOne({"Value1":190, "Value2":210}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd3fe45edc6604c74817cec") }Following is the query to display all documents from a collection with the help of ... Read More

Let us first create a collection with documents −>db.missingDocumentDemo.insertOne({"StudentFirstName":"Adam", "StudentLastName":"Smith"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd3fb1eedc6604c74817ce6") } >db.missingDocumentDemo.insertOne({"StudentFirstName":"Carol", "StudentLastName":"Taylor"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd3fb29edc6604c74817ce7") } >db.missingDocumentDemo.insertOne({"StudentFirstName":"David", "StudentLastName":"Miller", "StudentAge":21}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd3fb40edc6604c74817ce8") }Following is the query to display all documents from a collection with the help of find() method −> db.missingDocumentDemo.find().pretty();This will produce the following output −{    "_id" : ObjectId("5cd3fb1eedc6604c74817ce6"),    "StudentFirstName" : "Adam",    "StudentLastName" : "Smith" } {    "_id" : ObjectId("5cd3fb29edc6604c74817ce7"),    "StudentFirstName" : "Carol",    "StudentLastName" : "Taylor" } {    "_id" : ... Read More

You can use $and operator for this. Let us first create a collection with documents −> db.twoSpecificIdsDemo.insertOne( ...   { ...      PlayerId:1, ...      "PlayerDetails": [{ ...         id: 100, ...         "PlayerName":"Chris" ...      }, { ...         id: 101, ...         "PlayerName":"Sam" ...      }, { ...         id: 102, ...         "PlayerName":"Robert" ...      }, { ...         id: 103, ...         "PlayerName":"Carol" ...      }] ... Read More

Use $pull operator along with positional operator($) in MongoDB. Let us first create a collection with documents −> db.pullWithPositionalOperatorDemo.insertOne( ...   { ...      _id: 100, ...      "StudentDetails": [ ...         { ...            "StudentId": "STU-1", ...            "StudentFavouriteSubject": ["MongoDB", "Java"] ...         }, ...         { ...            "StudentId": "STU-2", ...            "StudentFavouriteSubject": ["PHP", "MySQL"] ...         } ...      ] ...   } ... ); { ... Read More

To search a sub-filed in MongoDB, you can use double quotes along with dot notation. Let us first create a collection with documents −> db.searchSubFieldDemo.insertOne( ...   { ...      "UserDetails": ...      {"UserEmailId":"John123@gmail.com", "UserAge":21} ...   } ... ); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd3d909edc6604c74817ce2") } > db.searchSubFieldDemo.insertOne( { "UserDetails": {"UserEmailId":"Carol@yahoo.com", "UserAge":26} } ); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd3d9a4edc6604c74817ce3") }Following is the query to display all documents from a collection with the help of find() method −> db.searchSubFieldDemo.find().pretty();This will produce the following output −{    "_id" : ObjectId("5cd3d909edc6604c74817ce2"),    "UserDetails" ... Read More