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For this, use $elemMatch, which is used to query nested objects. Let us create a collection with documents −> db.demo444.insertOne( ... { ... "Information": [{ ... id:1, ... Name:"Chris" ... }] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e78ea87bbc41e36cc3caebf") } > db.demo444.insertOne( ... { ... "Information": [{ ... id:2, ... Name:"David" ... }] ... } ... ); { "acknowledged" : true, ... Read More
The simplest way to replace records is using MySQL REPLACE() −mysql> create table DemoTable2025 -> ( -> URL text -> ); Query OK, 0 rows affected (0.88 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2025 values('http=//www.facebook.com'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable2025 values('http=//www.google.com'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable2025 values('http=//www.gmail.com'); Query OK, 1 row affected (0.26 sec)Display all records from the table using select statement −mysql> select *from DemoTable2025;This will produce the following output −+-------------------------+ | URL ... Read More
The following operations are treated as command operation in MongoDB −1.count 2.findAndModify 3.aggregateFollowing is the example of count in MongoDB −Let us create a collection with documents −> db.demo443.insertOne({"Name":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5e78d281bbc41e36cc3caeb9") } > db.demo443.insertOne({"Name":"Bob"}); { "acknowledged" : true, "insertedId" : ObjectId("5e78d285bbc41e36cc3caeba") } > db.demo443.insertOne({"Name":"David"}); { "acknowledged" : true, "insertedId" : ObjectId("5e78d288bbc41e36cc3caebb") }Display all documents from a collection with the help of find() method −> db.demo443.find();This will produce the following output −{ "_id" : ObjectId("5e78d281bbc41e36cc3caeb9"), "Name" : "Chris" } { "_id" : ObjectId("5e78d285bbc41e36cc3caeba"), "Name" : "Bob" } { "_id" : ... Read More
For this, use GROUP_CONCAT(). Let us first create a table −mysql> create table DemoTable2024 -> ( -> SubjectName varchar(20), -> StudentName varchar(20) -> ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2024 values('MySQL', 'Chris'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable2024 values('MySQL', 'David'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable2024 values('MongoDB', 'Bob'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable2024 values('Java', 'Sam'); Query OK, 1 row affected (0.18 sec) mysql> ... Read More
To get distinct values from object array in MongoDB, use distinct(). Let us create a collection with documents −> db.demo442.insertOne( ... { ... ... "Information" : [ ... { ... "FirstName" : "John", ... "Age" : 21 ... }, ... { ... "FirstName" : "Sam", ... "Age" : 23 ... }, ... ... Read More
For this, use UPDATE command along with REGEXP. Let us first create a table −mysql> create table DemoTable2023 -> ( -> StreetNumber varchar(100) -> ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2023 values('7'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable2023 values('1'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable2023 values('AUS-100'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable2023 values('US-101'); Query OK, 1 row affected (0.11 sec)Display all records from the table using ... Read More
To aggregate nested array in MongoDB, use aggregate(). Let us create a collection with documents −> db.demo441.insertOne( ... { ... ... "Name" : "David", ... "Age" : 21, ... ... "details" : [ ... { ... "id" : 1, ... "CountryName" : "US", ... "details1" : [ ... { ... "SubjectName" : ... Read More
To insert multiple values in a column, the syntax is as follows −insert into yourTableName values(yourValue1), (yourValue2), ..........N;To understand the above syntax, let us create a table −mysql> create table DemoTable2022 -> ( -> Department varchar(100) -> ); Query OK, 0 rows affected (0.49 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2022 values('Computer Science'), ('Information Technology'), ('Civil'), ('Mechanical'), ('Electronics'), ('Electrical'); Query OK, 6 rows affected (0.46 sec) Records: 6 Duplicates: 0 Warnings: 0Display all records from the table using select statement −mysql> select *from DemoTable2022;This will produce the following ... Read More
To insert data from one scheme to another, the syntax is as follows. Here, we have two databases “yourDatabaseName1” and “yourDatabaseName2” −insert into yourDatabaseName2.yourTableName2 select *from yourDatabaseName1.yourTableName1;To understand the above syntax, let us create a table. We are creating a table in database “web” −mysql> create table DemoTable2020 -> ( -> Id int, -> Name varchar(20) -> ); Query OK, 0 rows affected (0.67 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2020 values(101, 'Chris'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable2020 values(102, 'David'); Query OK, 1 ... Read More
To count items in array, use length. Let us create a collection with documents −> db.demo440.insertOne( ... { ... "Name":"Chris", ... "ListOfFriends":["John", "Sam", "Mike"] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e78c63cbbc41e36cc3caeb5") } > > db.demo440.insertOne( ... { ... "Name":"David", ... "ListOfFriends":["Mike", "Bob", "Carol"] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e78c63cbbc41e36cc3caeb6") }Display all documents from a collection with the help of find() method −> db.demo440.find();This will produce the following output −{ "_id" : ... Read More