For this, use $where and compare with ==. Let us create a collection with documents −> db.demo69.insertOne( ... { ...    "_id" : ObjectId("507c7f79bcf86cd7994f6c0e"), ... "Details" : { ... ...    "id" : ObjectId("507c7f79bcf86cd7994f6c0e") ...    } ... } ... ); {    "acknowledged" : true,    "insertedId" : ObjectId("507c7f79bcf86cd7994f6c0e") ... Read More

To sort, use $match along with aggregate. Let us create a collection with documents −> db.demo67.insertOne({"StudentAge":23}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e289edf602d9a2ff1828ed8") } > db.demo67.insertOne({"StudentAge":21}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e289ee1602d9a2ff1828ed9") } > db.demo67.insertOne({"StudentAge":24}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e289ee3602d9a2ff1828eda") }Display ... Read More

To get index of an array element, use $indexOfArray. Let us create a collection with documents −> db.demo65.insertOne({"ListOfValues":[10, 20, 30]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e28990ecfb11e5c34d89938") } > db.demo65.insertOne({"ListOfValues":[50, 60, 70, 100]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e28991ecfb11e5c34d89939") } > db.demo65.insertOne({"ListOfValues":[30, 40, 89, 91, ... Read More

To merge, use aggregate() along with $PUSH. Let us create a collection with documents −> db.demo64.insertOne({"Subjects":["MySQL", "MongoDB", "Java"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e28762bcfb11e5c34d89936") } > db.demo64.insertOne({"Subjects":["Oracle", "Spring", "Python"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e28763fcfb11e5c34d89937") }Display all documents from a collection with the help ... Read More

You need to use $group to group documents with specified _id expression. Let us first create a collection with documents −> db.aggreagateDemo.insertOne({"Product_Id":1, "ProductPrice":50}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e06d3c025ddae1f53b621d9") } > db.aggreagateDemo.insertOne({"Product_Id":2, "ProductPrice":100}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e06d3c625ddae1f53b621da") } > db.aggreagateDemo.insertOne({"Product_Id":2, "ProductPrice":500}); { ... Read More

To check for existence of a record, use findOne() in MongoDB. Let us first create a collection with documents −> db.existsAlternateDemo.insertOne({"StudentName":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e06d23f9e4dae213890ac5c") } > db.existsAlternateDemo.insertOne({"StudentName":"Chris", "StudentAge":21}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e06d2559e4dae213890ac5d") } >db.existsAlternateDemo.insertOne({"StudentName":"Chris", "StudentAge":22, "StudentCountryName":"US"}); {    "acknowledged" ... Read More

To sum specific fields, use aggregate along with $sum. Let us first create a collection with documents −> db.getSumOfFieldsDemo.insertOne({"Customer_Id":101, "Price":50, "Status":"Active"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e06cec29e4dae213890ac55") } > db.getSumOfFieldsDemo.insertOne({"Customer_Id":102, "Price":200, "Status":"Inactive"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e06ced19e4dae213890ac56") } > db.getSumOfFieldsDemo.insertOne({"Customer_Id":101, "Price":3000, "Status":"Active"}); { ... Read More

To insert records in MongoDB and avoid duplicates, use “unique:true”. Let us first create a collection with documents.Here, we are trying to add duplicate records −> db.insertWithoutDuplicateDemo.createIndex({"StudentFirstName":1}, { unique: true } ); {    "createdCollectionAutomatically" : true,    "numIndexesBefore" : 1,    "numIndexesAfter" : 2,    "ok" : 1 } ... Read More

To apply a condition, use $setIsSubset. Let us first create a collection with documents −> db.subsetDemo.insertOne({"StudentName":"Chris", "StudentFavouriteSubject":["Java", "Python"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e063e49150ee0e76c06a052") } > db.subsetDemo.insertOne({"StudentName":"Chris", "StudentFavouriteSubject":["Java", "Python", "MySQL"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e063e4f150ee0e76c06a053") }Following is the query to display all documents ... Read More

At first, get the current month and subtract by 1 to fetch previous month records. Let us first create a collection with documents −> db.findOneMonthAgoData.insertOne({"CustomerName":"Chris", "PurchaseDate":new ISODate("2019-12-26")}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e04e16c150ee0e76c06a04f") } > db.findOneMonthAgoData.insertOne({"CustomerName":"David", "PurchaseDate":new ISODate("2019-11-26")}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e04e178150ee0e76c06a050") ... Read More