To find the oldest date, use $min in MongoDB aggregate(). Let us create a collection with documents −> db.demo353.insertOne({"Date1":new ISODate("2019-01-10"), "Date2":new ISODate("2016-01-21"), "Date3":new ISODate("2020-04-11")}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e568261f8647eb59e5620be") } > db.demo353.insertOne({"Date1":new ISODate("2011-11-20"), "Date2":new ISODate("2013-12-10"), "Date3":new ISODate("2014-01-05")}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e56827ff8647eb59e5620bf") }Display all documents from a collection with the help of find() method −> db.demo353.find();This will produce the following output −{ "_id" : ObjectId("5e568261f8647eb59e5620be"), "Date1" : ISODate("2019-01-10T00:00:00Z"), "Date2" : ISODate("2016-01-21T00:00:00Z"), "Date3" : ISODate("2020-04-11T00:00:00Z") } { "_id" : ObjectId("5e56827ff8647eb59e5620bf"), "Date1" : ISODate("2011-11-20T00:00:00Z"), "Date2" : ISODate("2013-12-10T00:00:00Z"), "Date3" : ISODate("2014-01-05T00:00:00Z") }Following is the query ... Read More

To update selected fields, use UPDATE() in MongoDB. The $set is used to set the new value. Let us create a collection with documents −> db.demo352.insertOne({"Name":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e55510af8647eb59e5620ba") } > db.demo352.insertOne({"Name":"David"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e55510ef8647eb59e5620bb") } > db.demo352.insertOne({"Name":"Bob"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e555112f8647eb59e5620bc") } > db.demo352.insertOne({"Name":"Mike"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e555115f8647eb59e5620bd") }Display all documents from a collection with the help of find() method −> db.demo352.find();This will produce the following output −{ "_id" : ObjectId("5e55510af8647eb59e5620ba"), "Name" : "Chris" } { "_id" ... Read More

For this, use aggregate() in MongoDB. Let us create a collection with documents −> db.demo351.insertOne( ... { ... ...    "_id" : "101", ...    "ProductDetails" : [ ...       { ...          "ProductName" : "Product-1", ...          "ProductPrice" :500 ...       }, ...       { ...          "ProductName" : "Product-2", ...          "ProductPrice" :400 ...       } ...    ] ... } ... ); { "acknowledged" : true, "insertedId" : "101" } > db.demo351.insertOne( ... { ... ...   ... Read More

To query deeply nested objects, use dot(.) notation in MongoDB. Let us create a collection with documents −> db.demo350.insertOne( ... { ...    id:101, ...    Name: "Chris", ...    details: [ ...       { ...          _id: 1, ...          ClientNumber: "10001", ...          ClientDetails: [ . ...             { ...                Name:"David", ...                Age:29 ...             }, ...             ... Read More

The findOneAndUpdate() is used to update only a single document in MongoDB. Let us create a collection with documents −db.demo349.insertOne({"Name":"Chris", "Marks":56}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e55384af8647eb59e5620b4") } > db.demo349.insertOne({"Name":"David", "Marks":78}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e553853f8647eb59e5620b5") } > db.demo349.insertOne({"Name":"Chris", "Marks":89}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e55385af8647eb59e5620b6") } > db.demo349.insertOne({"Name":"David", "Marks":54}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e55385ff8647eb59e5620b7") }Display all documents from a collection with the help of find() method −> db.demo349.find();This will produce the following output −{ "_id" : ObjectId("5e55384af8647eb59e5620b4"), "Name" : "Chris", "Marks" : 56 } { ... Read More

To unset objects in MongoDB, use $unset. Let us create a collection with documents −> db.demo348.insertOne( ...    { ...    "details": { ...       "studentDetails": ...          { ...             StudentName: "Robert" ...          } ...    } ... ... }); {    "acknowledged" : true,    "insertedId" : ObjectId("5e553556f8647eb59e5620b2") } > db.demo348.insertOne( ... { ...    "details": { ...       "studentDetails": ...          { ...             StudentName: "Mike" ...          } ... ... Read More

To check duplicates in the inner array, use aggregate() in MongoDB. Let us create a collection with documents −> db.demo347.insertOne( ...    { ...       "details": { ...          "details1": [ ...             { ...                Name: "Chris", ...                Age: 21 ...             } ... ...          ] ...       } ...    } ... ); {    "acknowledged" : true,    "insertedId" : ObjectId("5e5532eaf8647eb59e5620af") } > ... Read More

To query an array of embedded documents based on range, use aggregate(). Let us create a collection with documents −> db.demo346.insertOne( ...    { ...       _id: 101, ...       userDetails: [ ...          { UserName: "Chris", Score:78}, ...          { UserName: "David", Score:68}, ...          { UserName: "Bob", Score:88} ...       ] ...    } ... ); { "acknowledged" : true, "insertedId" : 101 } > db.demo346.insertOne( ...    { ...       _id: 102, ...       userDetails: [ ...   ... Read More

Let us create a collection with documents −> db.demo345.insertOne({ ...    "UserName" : "Robert", ...       "UserDetails" : [ ...          { ...             "isMarried" : false, ...             "CountryName":"US" ... ...          }, ...          { ...             "isMarried" : true, ...             "CountryName":"UK" ... ...          }, ...          { ...             "isMarried" : false, ... ... Read More

Let us create a collection with documents −> db.demo344.insertOne({"startDate":"2020-02-24 10:50:00", "endDate":"2020-02-24 11:50:00"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e53f52cf8647eb59e5620aa") } > db.demo344.insertOne({"startDate":"2020-02-24 08:00:00", "endDate":"2020-02-24 11:50:50"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e53f53df8647eb59e5620ab") }Display all documents from a collection with the help of find() method −> db.demo344.find();This will produce the following output −{ "_id" : ObjectId("5e53f52cf8647eb59e5620aa"), "startDate" : "2020-02-24 10:50:00", "endDate" : "2020-02-24 11:50:00" } { "_id" : ObjectId("5e53f53df8647eb59e5620ab"), "startDate" : "2020-02-24 08:00:00", "endDate" : "2020-02-24 11:50:50" }Following is how to query objects with the longest time period −> db.demo344.aggregate([ ...    { $addFields: { ...   ... Read More