To randomize unique data, use Math.random() in MongoDB. Let us create a collection with documents −> db.demo561.insertOne({EmailId:null});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f490454b4472ed3e8e86c") } > db.demo561.insertOne({EmailId:null});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f490654b4472ed3e8e86d") } > db.demo561.insertOne({EmailId:null});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f490a54b4472ed3e8e86e") }Display all documents from a collection with the help of find() method −> db.demo561.find();This will produce the following output −{ "_id" : ObjectId("5e8f490454b4472ed3e8e86c"), "EmailId" : null } { "_id" : ObjectId("5e8f490654b4472ed3e8e86d"), "EmailId" : null } { "_id" : ObjectId("5e8f490a54b4472ed3e8e86e"), "EmailId" : null }Following is the query for randomizing unique data with MongoDB −> db.demo561.find().forEach(function(doc){ ...   ... Read More

To match, use $match in MongoDB and to get data between two dates, use $gte and $lte. Let us create a collection with documents −> db.demo560.insertOne({"value1":40, "value2":40, shippingDate:new ISODate("2020-02-26")});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f3d5254b4472ed3e8e867") } > db.demo560.insertOne({"value1":20, "value2":60, shippingDate:new ISODate("2020-02-26")});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f3d5254b4472ed3e8e868") } > db.demo560.insertOne({"value1":40, "value2":70, shippingDate:new ISODate("2020-03-31")});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f3d5254b4472ed3e8e869") } > db.demo560.insertOne({"value1":40, "value2":130, shippingDate:new ISODate("2020-03-31")});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f3d5254b4472ed3e8e86a") }Display all documents from a collection with the help of find() method −> db.demo560.find();This will produce the following output −{ "_id" : ObjectId("5e8f3d5254b4472ed3e8e867"), "value1" : ... Read More

To GROUP BY array of the document, use $group. Let us create a collection with documents −>db.demo559.insertOne({details:[{Name:"Chris", Age:21}, {Name:"Bob", Age:22}, {Name:"Carol", Age:21}, {Name:"Sam", Age:21}]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e8f38d954b4472ed3e8e866") }Display all documents from a collection with the help of find() method −> db.demo559.find().pretty();This will produce the following output −{    "_id" : ObjectId("5e8f38d954b4472ed3e8e866"),    "details" : [       {          "Name" : "Chris",          "Age" : 21       },       {          "Name" : "Bob",          "Age" : ... Read More

Let us see an example and create a collection with documents −> db.demo558.insertOne( ... { ...    _id : 100, ...    CountryCode:101, ...    details: [ ...       { ...          Name:"Chris", ...          Subject:"MySQL" ...       }, ...       { ...          Name:"Chris", ...          Subject:"MongoDB" ...       }, ...       { ...          Name:"Chris", ...          Subject:"Java" ...       }, ...       { ...   ... Read More

Let us see an example and create a collection with documents −> db.demo557.insertOne({Name:"Chris"});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f28e954b4472ed3e8e864") } > db.demo557.insertOne({Name:"David"});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f28ee54b4472ed3e8e865") }Display all documents from a collection with the help of find() method −> db.demo557.find();This will produce the following output −{ "_id" : ObjectId("5e8f28e954b4472ed3e8e864"), "Name" : "Chris" } { "_id" : ObjectId("5e8f28ee54b4472ed3e8e865"), "Name" : "David" }Following is the query to update only a specific field value −> db.getCollection('demo557').update({Name:"Chris"}, {$set:{Name:"Robert"}}); WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })Display all documents from a collection with the help of find() method ... Read More

To fetch records from a subdocument array, use $unwind along with $push. For ids beginning from 234, use regex in MongoDB.Let us create a collection with documents −> db.demo556.insertOne( ... { ...    _id:101, ...    details:[ ...       { ...          id:"234336", ...          Name:"Chris" ...       }, ...       { ...          id:"123456", ...          Name:"Bob" ...       }, ...       { ...          id:"234987", ...          Name:"Carol" ...   ... Read More

To match a specific field value, use a $match in MongoDB aggregation. Let us create a collection with documents −> db.demo555.insertOne({"CountryName":"US"});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f21bf54b4472ed3e8e85f") } > db.demo555.insertOne({"CountryName":"UK"});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f21c254b4472ed3e8e860") } > db.demo555.insertOne({"CountryName":"US"});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f21c354b4472ed3e8e861") } > db.demo555.insertOne({"CountryName":"AUS"});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f21c554b4472ed3e8e862") } > db.demo555.insertOne({"CountryName":"US"});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f21c754b4472ed3e8e863") }Display all documents from a collection with the help of find() method −> db.demo555.find();This will produce the following output: −{ "_id" : ObjectId("5e8f21bf54b4472ed3e8e85f"), "CountryName" : "US" } { "_id" : ObjectId("5e8f21c254b4472ed3e8e860"), "CountryName" ... Read More

For “like” implementation in MongoDB, use / / and set that specific letter in between. For example −/J/Let us create a collection with documents −> db.demo554.insertOne({"UserName":"John", "UserMailId":"John@gmail.com"});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f1cfed1d72c4545cb8679") } > db.demo554.insertOne({"UserName":"Chris", "UserMailId":"Chris@gmail.com"});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f1d0cd1d72c4545cb867a") } > db.demo554.insertOne({"UserName":"Jace", "UserMailId":"Jace@gmail.com"});{    "acknowledged" : true, "insertedId" : ObjectId("5e8f1d1cd1d72c4545cb867b") }Display all documents from a collection with the help of find() method −> db.demo554.find();This will produce the following output −{ "_id" : ObjectId("5e8f1cfed1d72c4545cb8679"), "UserName" : "John", "UserMailId" : "John@gmail.com" } { "_id" : ObjectId("5e8f1d0cd1d72c4545cb867a"), "UserName" : "Chris", "UserMailId" : "Chris@gmail.com" } { "_id" : ... Read More

For this, use findOneAndUpdate() in MongoDB. The findOneAndUpdate() method updates a single document based on the filter and sort criteria.Let us create a collection with documents −> db.demo553.insertOne( ... { ...    id:101, ...    "Name":"John", ...    midExamDetails: ...    [ ...       {"SubjectName":"MySQL", "Marks":70}, ...       {"SubjectName":"MongoDB", "Marks":35} ...    ] ... } ... ); {    "acknowledged" : true,    "insertedId" : ObjectId("5e8e3da19e5f92834d7f05ed") }Display all documents from a collection with the help of find() method −> db.demo553.find();This will produce the following output −{ "_id" : ObjectId("5e8e3da19e5f92834d7f05ed"), "id" : 101, "Name" : "John", "midExamDetails" ... Read More

Use aggregate() in MongoDB to select documents with values above the average. To find the average, use $avg in MongoDB.Let us create a collection with documents −> db.demo552.insertOne({values:10});{    "acknowledged" : true, "insertedId" : ObjectId("5e8e3b1c9e5f92834d7f05ea") } > db.demo552.insertOne({values:50});{    "acknowledged" : true, "insertedId" : ObjectId("5e8e3b1f9e5f92834d7f05eb") } > db.demo552.insertOne({values:40});{    "acknowledged" : true, "insertedId" : ObjectId("5e8e3b289e5f92834d7f05ec") }Display all documents from a collection with the help of find() method −> db.demo552.find();This will produce the following output −{ "_id" : ObjectId("5e8e3b1c9e5f92834d7f05ea"), "values" : 10 } { "_id" : ObjectId("5e8e3b1f9e5f92834d7f05eb"), "values" : 50 } { "_id" : ObjectId("5e8e3b289e5f92834d7f05ec"), "values" : 40 }Following is the ... Read More