To query MongoDB using the $ne operator, following is the syntax −db.yourCollectionName.find({yourFieldName:{$ne:yourValue}}).pretty();Let us create a collection with documents −> db.notEqaulToDemo.insertOne({"StudentName":"Larry", "StudentMathMarks":68}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd3a6bde8cc557214c0ded") } > db.notEqaulToDemo.insertOne({"StudentName":"Chris", "StudentMathMarks":88}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd3a79de8cc557214c0dee") } > db.notEqaulToDemo.insertOne({"StudentName":"David", "StudentMathMarks":45}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd3a89de8cc557214c0def") } > db.notEqaulToDemo.insertOne({"StudentName":"Carol", "StudentMathMarks":69}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd3a97de8cc557214c0df0") }Display all documents from a collection with the help of find() method −> db.notEqaulToDemo.find().pretty();This will produce the following output −{    "_id" : ObjectId("5cbd3a6bde8cc557214c0ded"),    "StudentName" : "Larry",    "StudentMathMarks" : ... Read More

Use $unset operator to unset an attribute. Let us first create a collection with documents −> db.unsetAnAttributeDemo.insertOne( ...    { ...       _id: 1, ...       "StudentDetails": [ ...          { ...             "StudentFirstName": "Ramit", ...             "StudentCountryName":"UK" ...          }, ...          { ...             "StudentFirstName": "Bob", ...             "StudentCountryName":"US" ...          }, ...          { ...       ... Read More

You can use $ne operator for this. Let us first create a collection with documents −> db.searchByPropertyName.insertOne({"FirstName":"Larry", "Age":23}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbaf7af7219729fde21ddb5") } > db.searchByPropertyName.insertOne({"FirstName":null, "Age":21}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbaf7b97219729fde21ddb6") } > db.searchByPropertyName.insertOne({"FirstName":"John", "Age":22}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbaf7c57219729fde21ddb7") } > db.searchByPropertyName.insertOne({"FirstName":null, "Age":25}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbaf7d07219729fde21ddb8") } > db.searchByPropertyName.insertOne({"FirstName":"David", "Age":20}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbaf7df7219729fde21ddb9") }Following is the query to display all documents from the collection with the help of find() prettyprint −> db.searchByPropertyName.find().pretty();This will produce ... Read More

You can use $not operator along with $type for this. Let us first create a collection with documents −> db.highestNumericValueOfAColumnDemo.insertOne( ...    { ...       "StudentName": "John", ...       "StudentMathMarks":69 ...    } ... ); {    "acknowledged" : true,    "insertedId" : ObjectId("5cba05727219729fde21ddb1") } > db.highestNumericValueOfAColumnDemo.insertOne( ...    { ...       "StudentName": "Carol", ...       "StudentMathMarks":"89" ...    } ... ); {    "acknowledged" : true,    "insertedId" : ObjectId("5cba059d7219729fde21ddb2") } > db.highestNumericValueOfAColumnDemo.insertOne( ...    { ...       "StudentName": "Chris", ...       "StudentMathMarks":82 ...    } ... ... Read More

To delete a MongoDB field and value, you can use $unset operator. Let us first create a collection with documents −> db.deleteFieldDemo.insertOne({"FirstName":"John", "LastName":"Smith"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cb9fb767219729fde21ddad") } > db.deleteFieldDemo.insertOne({"FirstName":"David", "LastName":"Miller"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cb9fb837219729fde21ddae") } > db.deleteFieldDemo.insertOne({"FirstName":"Carol", "LastName":"Taylor"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cb9fb8d7219729fde21ddaf") }Following is the query to display all documents from the collection with the help of find() method −> db.deleteFieldDemo.find().pretty();This will produce the following output −{    "_id" : ObjectId("5cb9fb767219729fde21ddad"),    "FirstName" : "John",    "LastName" : "Smith" } {    "_id" : ... Read More

You can use dot(.) notation to read a specific key-value pair from MongoDB collection. Let us first create a collection with documents −> db.readSpecificKeyValueDemo.insertOne( ...    { ...       "_id": 100, ...       "StudentDetails": ...       { ...          "StudentFirstName" : "David", ...          "StudentLastName" :"Miller", ...          "StudentAge":23, ...          "StudentCountryName":"US" ...       } ...    } ... ); { "acknowledged" : true, "insertedId" : 100 }Following is the query to display all documents from the collection with the ... Read More

You can use aggregate framework along with $setUnion operator. Let us first create a collection with documents −> db.removeDuplicatesDemo.insertOne({"InstructorName":"Chris", "InstructorAge":34, "InstructorSubject":    ["Java", "C", "Java", "C++", "MongoDB", "MySQL", "MongoDB"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cb9d96c895c4fd159f80807") }Following is the query to display all documents from the collection with the help of find() method −> db.removeDuplicatesDemo.find().pretty();This will produce the following output −{    "_id" : ObjectId("5cb9d96c895c4fd159f80807"),    "InstructorName" : "Chris",    "InstructorAge" : 34,    "InstructorSubject" : [       "Java",       "C",       "Java",       "C++",       "MongoDB",   ... Read More

You can use $all operator. Let us first create a collection with documents −> db.subsetOfAnArrayDemo.insertOne({"StudentProgrammingSkills":    ["Java", "MongoDB", "MySQL", "C++", "Data Structure", "Algorithm", "Python", "Oracle", "SQL Server"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cb9d1e1895c4fd159f80804") }Following is the query to display all documents from the collection with the help of find() method −> db.subsetOfAnArrayDemo.find().pretty();This will produce the following output −{    "_id" : ObjectId("5cb9d1e1895c4fd159f80804"),    "StudentProgrammingSkills" : [       "Java",       "MongoDB",       "MySQL",       "C++",       "Data Structure",       "Algorithm",       "Python",     ... Read More

To extract the subarray value in MongoDB, you can use $elemMatch projection operator.Let us first create a collection with documents −> db.extractSubArrayDemo.insertOne( ...    { ...       _id: 101, ...       "clientName":"Larry", ...       "ClientDetails": ...       [ ...          { ...             "ClientProjectName":"Online Game", ...             "DeveloperTeamSize": 10 ...          }, ...          { ...             "ClientProjectName":"Pig Dice Game", ...             "DeveloperTeamSize": ... Read More

You can use aggregate framework along with $month projection operator. Let us first create a collection with documents −> db.specificMonthDemo.insertOne({"StudentName":"Larry", "StudentDateOfBirth":new ISODate('1995-01-12')}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cb9a9ca8f1d1b97daf71819") } > db.specificMonthDemo.insertOne({"StudentName":"Chris", "StudentDateOfBirth":new ISODate('1999-12-31')}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cb9a9db8f1d1b97daf7181a") } > db.specificMonthDemo.insertOne({"StudentName":"David", "StudentDateOfBirth":new ISODate('2000-06-01')}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cb9a9ee8f1d1b97daf7181b") }Following is the query to display all documents from the collection with the help of find() method −> db.specificMonthDemo.find().pretty();This will produce the following output −{    "_id" : ObjectId("5cb9a9ca8f1d1b97daf71819"),    "StudentName" : "Larry",    "StudentDateOfBirth" : ISODate("1995-01-12T00:00:00Z") } {    "_id" ... Read More