Let us first create a collection with documents −> db.demo270.insertOne({"ClientName":"Chirs", "Age":34}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e481e371627c0c63e7dbab8") } > db.demo270.insertOne({"ClientName":"David", "Age":31}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e481e3d1627c0c63e7dbab9") } > db.demo270.insertOne({"ClientName":"Bob", "Age":31}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e481e431627c0c63e7dbaba") } > db.demo270.insertOne({"ClientName":"Carol", "Age":36}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e481e491627c0c63e7dbabb") }Display all documents from a collection with the help of find() method −> db.demo270.find();This will produce the following output −{ "_id" : ObjectId("5e481e371627c0c63e7dbab8"), "ClientName" : "Chirs", "Age" : 34 } { "_id" : ObjectId("5e481e3d1627c0c63e7dbab9"), "ClientName" : "David", "Age" : 31 } ... Read More

For this, simply use find(). Set the fields you don’t want to select to 0. Let us create a collection with documents −> db.demo269.insertOne({StudentId:101, StudentSubject:"MySQL"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e481caa1627c0c63e7dbab4") } > db.demo269.insertOne({StudentId:102, StudentSubject:"Java"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e481cb11627c0c63e7dbab5") } > db.demo269.insertOne({StudentId:103, StudentSubject:"MongoDB"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e481cb21627c0c63e7dbab6") } > db.demo269.insertOne({StudentId:104, StudentSubject:"C"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e481cb21627c0c63e7dbab7") }Display all documents from a collection with the help of find() method −> db.demo269.find();This will produce the following output −{ "_id" : ObjectId("5e481caa1627c0c63e7dbab4"), "StudentId" : 101, "StudentSubject" ... Read More

To search a value, simply use $where in MongoDB. Let us create a collection with documents −> db.demo268.insertOne( ...   { ...      "details" : { ...         "101" : "John", ...         "1001" : "Bob" ...      } ...   } ...); {    "acknowledged" : true,    "insertedId" : ObjectId("5e4816141627c0c63e7dbaaf") }Display all documents from a collection with the help of find() method −> db.demo268.find();This will produce the following output −{ "_id" : ObjectId("5e4816141627c0c63e7dbaaf"), "details" : { "101" : "John", "1001" : "Bob" } }Following is the query to search a ... Read More

For descending order, use -1, which specifies sorting order for sort(), Let us create a collection with documents −> db.demo267.insertOne({id:100, "Name":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e4811951627c0c63e7dbaab") } > db.demo267.insertOne({id:100, "Name":"Adam"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e48119e1627c0c63e7dbaac") } > db.demo267.insertOne({id:100, "Name":"David"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e4811a51627c0c63e7dbaad") } > db.demo267.insertOne({id:100, "Name":"Bob"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e4811ab1627c0c63e7dbaae") }Display all documents from a collection with the help of find() method −> db.demo267.find().pretty(); {    "_id" : ObjectId("5e4811951627c0c63e7dbaab"),    "id" : 100,    "Name" : "Chris" } {    "_id" ... Read More

The $not operator won’t invert a complex expression. Therefore, use $and or $or with $ne operator.Let us create a collection with documents −> db.demo266.insertOne({"active1":true, "active2":false}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e480f4b1627c0c63e7dbaa7") } > db.demo266.insertOne({"active1":true, "active2":true}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e480f501627c0c63e7dbaa8") } > db.demo266.insertOne({"active1":false, "active2":false}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e480f561627c0c63e7dbaa9") } > db.demo266.insertOne({"active1":false, "active2":true}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e480f701627c0c63e7dbaaa") }Display all documents from a collection with the help of find() method −> db.demo266.find();This will produce the following output −{ "_id" : ObjectId("5e480f4b1627c0c63e7dbaa7"), "active1" : true, "active2" ... Read More

To update only certain fields, use $set. Let us create a collection with documents −> db.demo265.insertOne({"id":101, "Name":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e480d781627c0c63e7dbaa4") } > db.demo265.insertOne({"id":102, "Name":"Bob"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e480d7d1627c0c63e7dbaa5") } > db.demo265.insertOne({"id":103, "Name":"David"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e480d841627c0c63e7dbaa6") }Display all documents from a collection with the help of find() method −> db.demo265.find();This will produce the following output −{ "_id" : ObjectId("5e480d781627c0c63e7dbaa4"), "id" : 101, "Name" : "Chris" } { "_id" : ObjectId("5e480d7d1627c0c63e7dbaa5"), "id" : 102, "Name" : "Bob" } { "_id" : ObjectId("5e480d841627c0c63e7dbaa6"), "id" : 103, ... Read More

To get the count and top users, use $group along with aggregate() . Let us create a collection with documents −> db.demo264.insertOne({"Name":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e47ed441627c0c63e7dba9e") } > db.demo264.insertOne({"Name":"David"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e47ed471627c0c63e7dba9f") } > db.demo264.insertOne({"Name":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e47ed491627c0c63e7dbaa0") } > db.demo264.insertOne({"Name":"Bob"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e47ed4c1627c0c63e7dbaa1") } > db.demo264.insertOne({"Name":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e47ed4e1627c0c63e7dbaa2") } > db.demo264.insertOne({"Name":"Bob"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e47ed531627c0c63e7dbaa3") }Display all documents from a collection with the help ... Read More

To skip documents in MongoDB, use skip(). Let us create a collection with documents −> db.demo263.insertOne({_id:100}); { "acknowledged" : true, "insertedId" : 100 } > db.demo263.insertOne({_id:200}); { "acknowledged" : true, "insertedId" : 200 } > db.demo263.insertOne({_id:300}); { "acknowledged" : true, "insertedId" : 300 }Display all documents from a collection with the help of find() method −> db.demo263.find();This will produce the following output −{ "_id" : 100 } { "_id" : 200 } { "_id" : 300 }Following is the query to skip document −> result = db.demo263.aggregate([ ...   { ...      $project: { ...         v_id: { $ifNull: [null, [100, 200]] } ... ...      } ...   }, ...   { $unwind: '$v_id' }, ...   { $sort: { v_id: 1, _id: 1 } }, ... ...   { $skip: 2 }, ...   { $limit: 2 } ...]);This will produce the following output −{ "_id" : 300, "v_id" : 100 } { "_id" : 100, "v_id" : 200 }

To invert result i.e. opposite of $and operation, use $OR along with $ne. Let us first create a collection with documents −> db.demo4.insert({uid:1, "Name":"Chris", "Age":22}); WriteResult({ "nInserted" : 1 }) > db.demo4.insert({uid:2, "Name":"David", "Age":21}); WriteResult({ "nInserted" : 1 }) > db.demo4.insert({uid:3, "Name":"Bob", "Age":23}); WriteResult({ "nInserted" : 1 }) > db.demo4.insert({uid:1, "Name":"Carol", "Age":20}); WriteResult({ "nInserted" : 1 })Following is the query to display all documents from a collection with the help of find() method −> db.demo4.find();This will produce the following output −{ "_id" : ObjectId("5e0a1da125ddae1f53b62221"), "uid" : 1, "Name" : "Chris", "Age" : 22 } { "_id" : ObjectId("5e0a1db025ddae1f53b62222"), "uid" : ... Read More

To modify a sequence, use findAndModify(). Let us create a collection with documents −> db.demo261.insertOne({_id:100, Name:"Chris"}); { "acknowledged" : true, "insertedId" : 100 }Display all documents from a collection with the help of find() method −> db.demo261.find();This will produce the following output −{ "_id" : 100, "Name" : "Chris" }Following is the query to modify sequence −> db.demo262.insert({_id:"newId", sequence_value:0}) WriteResult({ "nInserted" : 1 }) > function getNext(sName){ ... ...   var d= db.demo262.findAndModify({ ...      query:{_id: sName}, ...      update: {$inc:{sequence_value:1}}, ...      new:true ...   }); ...   return d.sequence_value; ...}Following is the query to call ... Read More