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Database Articles
Page 211 of 546
Cannot push into an array from MongoDB?
To push into an array with MongoDB, use $push. Let us create a collection with documents −> db.demo445.insertOne({"ListOfFriends":["Robert", "Mike", "Sam", "Carol", "David", "Mike"]}); { "acknowledged" : true, "insertedId" : ObjectId("5e78f099bbc41e36cc3caec2") }Display all documents from a collection with the help of find() method −> db.demo445.find().pretty();This will produce the following output −{ "_id" : ObjectId("5e78f099bbc41e36cc3caec2"), "ListOfFriends" : [ "Robert", "Mike", "Sam", "Carol", "David", "Mike" ] }Following is the query to push into an array −> db.demo445.update( ... { ...
Read MoreHow to write a valid MySQL query and update with a custom variable?
Let us first create a table −mysql> create table DemoTable2027 -> ( -> UserId int -> ); Query OK, 0 rows affected (0.65 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2027 values(10); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable2027 values(20); Query OK, 1 row affected (0.28 sec) mysql> insert into DemoTable2027 values(31); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable2027 values(11); Query OK, 1 row affected (0.12 sec)Display all records from the table using select statement −mysql> select *from DemoTable2027;This will produce ...
Read MoreCan we add minutes to VARCHAR datetime records while applying INSERT statement in MySQL?
Yes, we can add minutes while inserting values in a table.Let us first create a table. Here, we have a column with VARCHAR records where inmysql> create table DemoTable2026 -> ( -> ArrivalTime varchar(20) -> ); Query OK, 0 rows affected (0.40 sec)Insert some records in the table using insert command. We are first converting the VARCHAR date and then adding minutes −mysql> insert into DemoTable2026 values(date_add(str_to_date('2017-12-01 11:34:45', '%Y-%m-%d %H:%i:%s'), INTERVAL 10 MINUTE)); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable2026 values(date_add(str_to_date('2015-01-31 10:00:00', '%Y-%m-%d %H:%i:%s'), INTERVAL 5 MINUTE)); Query OK, 1 row affected ...
Read MoreHow to improve MongoDB queries with multikey index in array?
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 MoreFind and replace a part of URL records in MySQL?
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 MoreMongoDB profiler output: What is the “command” operation?
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 MoreMySQL regular expression to update a table with column values including string, numbers and special characters
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 MoreHow do I insert multiple values in a column with a single MySQL query?
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 MoreInsert data from one schema to another in MySQL?
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 MoreProject field in MongoDB
To project field in MongoDB, use $project. Let us create a collection with documents −> db.demo439.insertOne( ... { ... "Name" : "Chris", ... "MarksInformation" : { ... "Marks1" : 67, ... "Marks2" :45, ... "Marks3" : 78 ... } ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e77833abbc41e36cc3caeab") } > db.demo439.insertOne( ... { ... "Name" : "David", ... "MarksInformation" : { ... ...
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