MongoDB Articles - Page 59 of 135

To compare fields from an array, use $gt and $lt. Let us create a collection with documents −> db.demo147.insertOne({"Details":[{"Score":45}, {"Score":46}]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32fa21fdf09dd6d08539be") } > db.demo147.insertOne({"Details":[{"Score":65}, {"Score":86}]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32fa40fdf09dd6d08539bf") }Display all documents from a collection with the help of find() method −> db.demo147.find().pretty();This will produce the following output −{    "_id" : ObjectId("5e32fa21fdf09dd6d08539be"),    "Details" : [       {          "Score" : 45       },       {          "Score" : 46       } ... Read More

To remove an array element, simply use $pull along with update(). Let us create a collection with documents −> db.demo146.insertOne({"ListOfEmployeeNames":["Chris", "David", "Bob", "Mike"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32f54ffdf09dd6d08539bd") }Display all documents from a collection with the help of find() method −> db.demo146.find();This will produce the following output −{ "_id" : ObjectId("5e32f54ffdf09dd6d08539bd"), "ListOfEmployeeNames" : [ "Chris", "David", "Bob", "Mike" ] }Following is the query to remove an array element from MongoDB −> db.demo146.update({}, { "$pull": { "ListOfEmployeeNames": "Bob" } }); WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })Display all documents from a collection with ... Read More

For writing an equality, you can simply use find() along with match value. Let us create a collection with documents −> db.demo145.insertOne({"ListOfNames":["Chris", "David", "Mike"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32f37bfdf09dd6d08539bb") } > db.demo145.insertOne({"ListOfNames":["Bob", "John"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32f384fdf09dd6d08539bc") }Display all documents from a collection with the help of find() method −> db.demo145.find();This will produce the following output −{ "_id" : ObjectId("5e32f37bfdf09dd6d08539bb"), "ListOfNames" : [ "Chris", "David", "Mike" ] } { "_id" : ObjectId("5e32f384fdf09dd6d08539bc"), "ListOfNames" : [ "Bob", "John" ] }Following is the query to implement MongoDB operator $eq −> db.demo145.find({"ListOfNames":"John"});This will produce ... Read More

Let us first create a collection with documents −>db.demo144.insertOne({"EmployeeDetails":[{"EmployeeName":"Chris", "EmployeeEmail":"Chris12@gmail.com"}, {"EmployeeName":"Bob", "EmployeeEmail":"bo22@gmail.com"}]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32f1d8fdf09dd6d08539b9") } >db.demo144.insertOne({"EmployeeDetails":[{"EmployeeName":"David", "EmployeeEmail":"david@gmail.com"}, {"EmployeeName":"Carol", "EmployeeEmail":"Carol@gmail.com"}]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32f1f5fdf09dd6d08539ba") }Display all documents from a collection with the help of find() method −> db.demo144.find();This will produce the following output −{    "_id" : ObjectId("5e32f1d8fdf09dd6d08539b9"), "EmployeeDetails" : [       { "EmployeeName" : "Chris", "EmployeeEmail" : "Chris12@gmail.com" },       { "EmployeeName" : "Bob", "EmployeeEmail" : "bo22@gmail.com" }    ] } {    "_id" : ObjectId("5e32f1f5fdf09dd6d08539ba"), "EmployeeDetails" : [       { "EmployeeName" ... Read More

For this, simply use update() to update. Let us create a collection with documents −> db.dem0143.insertOne({"StudentId":1, "Details":{"Name":"Chris"}}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32eb9efdf09dd6d08539b7") } > db.dem0143.insertOne({"StudentId":2, "Details":{"Name":"David"}}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32eba5fdf09dd6d08539b8") }Display all documents from a collection with the help of find() method −> db.dem0143.find();This will produce the following output −{ "_id" : ObjectId("5e32eb9efdf09dd6d08539b7"), "StudentId" : 1, "Details" : { "Name" : "Chris" } } { "_id" : ObjectId("5e32eba5fdf09dd6d08539b8"), "StudentId" : 2, "Details" : { "Name" : "David" } }Following is the query to implement $set and $push in a single update ... Read More

For this, you can use aggregate(). Let us create a collection with documents −> db.demo142.insertOne({"Value":50}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32e9c6fdf09dd6d08539b2") } > db.demo142.insertOne({"Value":45}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32e9cafdf09dd6d08539b3") } > db.demo142.insertOne({"Value":60}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32e9cdfdf09dd6d08539b4") } > db.demo142.insertOne({"Value":55}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32e9d0fdf09dd6d08539b5") } > db.demo142.insertOne({"Value":50}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e32e9d9fdf09dd6d08539b6") }Display all documents from a collection with the help of find() method −> db.demo142.find();This will produce the following output −{ "_id" : ObjectId("5e32e9c6fdf09dd6d08539b2"), "Value" : 50 } { ... Read More

To find last object in collection, at first sort() to sort the values. Use limit() to get number of values i.e. if you want only the last object, then use limit(1).Let us first create a collection with documents −> db.demo141.insertOne({"Name":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e31c347fdf09dd6d08539ae") } > db.demo141.insertOne({"Name":"David"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e31c34bfdf09dd6d08539af") } > db.demo141.insertOne({"Name":"Bob"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e31c34ffdf09dd6d08539b0") } > db.demo141.insertOne({"Name":"Mike"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e31c352fdf09dd6d08539b1") }Display all documents from a collection with the help of find() method −> db.demo141.find();This will ... Read More

For such kind of fetching, use only $nin and $in. Let us create a collection with documents −> db.demo140.insertOne({"Id":101, "Subjects":["MongoDB", "MySQL"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e31c149fdf09dd6d08539a9") } > db.demo140.insertOne({"Id":102, "Subjects":["MongoDB", "Java"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e31c14cfdf09dd6d08539aa") } > db.demo140.insertOne({"Id":103, "Subjects":["MongoDB", "PL/SQL"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e31c157fdf09dd6d08539ab") } > db.demo140.insertOne({"Id":104, "Subjects":["MongoDB", "SQL Server"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e31c163fdf09dd6d08539ac") } > db.demo140.insertOne({"Id":105, "Subjects":["C", "C++"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e31c16ffdf09dd6d08539ad") }Display all documents from a collection with the help of find() method −> ... Read More

For this, use aggregate(). Let us create a collection with documents −>db.demo138.insertOne({"Id":101, "PlayerDetails":[{"PlayerName":"Chris", "PlayerScore":400}, {"PlayerName":"David", "PlayerScore":1000}]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e31bb9ffdf09dd6d08539a1") } >db.demo138.insertOne({"Id":102, "PlayerDetails":[{"PlayerName":"Bob", "PlayerScore":500}, {"PlayerName":"Carol", "PlayerScore":600}]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e31bbcefdf09dd6d08539a2") }Display all documents from a collection with the help of find() method −> db.demo138.find();This will produce the following output −{    "_id" : ObjectId("5e31bb9ffdf09dd6d08539a1"), "Id" : 101, "PlayerDetails" : [       { "PlayerName" : "Chris", "PlayerScore" : 400 },       { "PlayerName" : "David", "PlayerScore" : 1000 }    ] } {    "_id" : ObjectId("5e31bbcefdf09dd6d08539a2"), ... Read More

For this, use aggregate() along with $filter. Let us create a collection with documents −> db.demo137.insertOne( ...    { ...       Name1:"Chris", ...       Name2:"David", ...       Detail1:[ ...          {_id:"John", Name3:"Chris"}, ...          {_id:"Chris", Name3:"Chris"}, ...       ], ...       Detail2:[{_id:"David", Name3:"Chris"}, ...       {_id:"Carol", Name3:"Chris"}, ...       {_id:"John", Name3:"Chris"}] ...    } ... ); {    "acknowledged" : true,    "insertedId" : ObjectId("5e31b4cefdf09dd6d08539a0") }Display all documents from a collection with the help of find() method −> db.demo137.find();This will ... Read More