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Database Articles
Page 457 of 546
Matching an array field that contains any combination of the provided array in MongoDB?
Use $nin operator along with $elemMatch and $not for this. To understand the concept, let us create a collection with the document. The query to create a collection with a document is as follows −> db.combinationOfArrayDemo.insertOne({"StudentName":"Larry", "StudentAge":21, "StudentFavouriteTechnicalSubject":["C", "Java"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c7f77cc8d10a061296a3c58") } > db.combinationOfArrayDemo.insertOne({"StudentName":"Mike", "StudentAge":23, "StudentFavouriteTechnicalSubject":["C++", "Java"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c7f77dc8d10a061296a3c59") } > db.combinationOfArrayDemo.insertOne({"StudentName":"David", "StudentAge":22, "StudentFavouriteTechnicalSubject":["Java"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c7f77f48d10a061296a3c5a") }Display all documents from a collection with the help of find() method. The query is as follows −> db.combinationOfArrayDemo.find().pretty();The following is the output ...
Read MoreMySQL update a column with an int based on order?
The syntax is as follows to update a column with an int based on orderset @yourVariableName=0; update yourTableName set yourColumnName=(@yourVariableName:=@yourVariableName+1) order by yourColumnName ASC;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table updateColumnDemo -> ( -> Id int, -> OrderCountryName varchar(100), -> OrderAmount int -> ); Query OK, 0 rows affected (1.76 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into updateColumnDemo(Id, OrderCountryName) values(10, 'US'); Query OK, 1 row affected (0.46 sec) mysql> insert into updateColumnDemo(Id, OrderCountryName) ...
Read MoreHow can I use 'Not Like' operator in MongoDB?
For this, use the $not operator in MongoDB. To understand the concept, let us create a collection with the document. The query to create a collection with a document is as follows −> db.notLikeOperatorDemo.insertOne({"StudentName":"John Doe"}); { "acknowledged" : true, "insertedId" : ObjectId("5c8a29c393b406bd3df60dfc") } > db.notLikeOperatorDemo.insertOne({"StudentName":"John Smith"}); { "acknowledged" : true, "insertedId" : ObjectId("5c8a29cc93b406bd3df60dfd") } > db.notLikeOperatorDemo.insertOne({"StudentName":"John Taylor"}); { "acknowledged" : true, "insertedId" : ObjectId("5c8a29df93b406bd3df60dfe") } > db.notLikeOperatorDemo.insertOne({"StudentName":"Carol Taylor"}); { "acknowledged" : true, "insertedId" : ObjectId("5c8a2a1693b406bd3df60dff") } > db.notLikeOperatorDemo.insertOne({"StudentName":"David Miller"}); { "acknowledged" : true, "insertedId" : ObjectId("5c8a2a2693b406bd3df60e00") }Display all documents from ...
Read MoreGet all MySQL records from the previous day (yesterday)?
To get the records from the previous day, the following is the syntaxselect *from yourTableName where date(yourColumnName)= DATE(NOW() - INTERVAL 1 DAY);To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table yesterDayRecordsDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> ArrivalDateTime datetime -> ); Query OK, 0 rows affected (0.44 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into yesterDayRecordsDemo(ArrivalDateTime) values('2014-11-09 13:45:21'); Query OK, 1 row affected (0.11 sec) mysql> insert into yesterDayRecordsDemo(ArrivalDateTime) values('2017-10-19 11:41:31'); Query ...
Read MoreFind duplicate records in MongoDB?
You can use the aggregate framework to find duplicate records in MongoDB. To understand the concept, let us create a collection with the document. The query to create a collection with a document is as follows −> db.findDuplicateRecordsDemo.insertOne({"StudentFirstName":"John"}); { "acknowledged" : true, "insertedId" : ObjectId("5c8a330293b406bd3df60e01") } > db.findDuplicateRecordsDemo.insertOne({"StudentFirstName":"John"}); { "acknowledged" : true, "insertedId" : ObjectId("5c8a330493b406bd3df60e02") } > db.findDuplicateRecordsDemo.insertOne({"StudentFirstName":"Carol"}); { "acknowledged" : true, "insertedId" : ObjectId("5c8a330c93b406bd3df60e03") } > db.findDuplicateRecordsDemo.insertOne({"StudentFirstName":"Sam"}); { "acknowledged" : true, "insertedId" : ObjectId("5c8a331093b406bd3df60e04") } > db.findDuplicateRecordsDemo.insertOne({"StudentFirstName":"Carol"}); { "acknowledged" : true, "insertedId" : ObjectId("5c8a331593b406bd3df60e05") } > db.findDuplicateRecordsDemo.insertOne({"StudentFirstName":"Mike"}); { ...
Read MoreIs it possible to delete everything after a 'space' in a MySQL field?
In order to delete everything after a space, you need to use SUBSTRING_INDEX().The syntax is as followsselect substring_index(yourColumnName, ' ', 1) as anyAliasName from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table deleteAfterSpaceDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(100) -> ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into deleteAfterSpaceDemo(StudentName) values('John Smith'); Query OK, 1 row affected (0.15 sec) mysql> insert into deleteAfterSpaceDemo(StudentName) ...
Read MoreCompare only day and month with date field in MySQL?
You can compare only day and month with date field in MySQL with the help of DATE_FORMAT().The syntax is as followsselect *from yourTableName WHERE DATE_FORMAT(yourColumnName, '%m-%d') = DATE_FORMAT('yourValue', '%m-%d') and yourCondition;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table compareDayAndMonthDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> compareDayAndTime date -> ); Query OK, 0 rows affected (0.49 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into compareDayAndMonthDemo(compareDayAndTime) values('2014-01-31'); Query OK, 1 row affected (0.20 ...
Read MorePrettyprint in MongoDB shell as default?
You can call pretty() function on cursor object to prettyprint in MongoDB shell. The syntax is as follows −db.yourCollectionName.find().pretty();To understand the concept, let us create a collection with the document. The query to create a collection with a document is as follows −>db.prettyDemo.insertOne({"ClientName":"Larry", "ClientAge":27, "ClientFavoriteCountry":["US", "UK"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c8a440de01f572ca0ccf5f2") } >db.prettyDemo.insertOne({"ClientName":"Mike", "ClientAge":57, "ClientFavoriteCountry":["AUS", "UK"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c8a4420e01f572ca0ccf5f3") }Display all documents from a collection with the help of find() method. The query is as follows −> db.prettyDemo.find();The following is the output −{ "_id" : ObjectId("5c8a440de01f572ca0ccf5f2"), "ClientName" : "Larry", "ClientAge" ...
Read MoreHow to add a where clause in a MySQL Insert statement?
You need to use UPDATE statement for this.The syntax is as followsupdate yourTableName set yourColumnName1=yourValue1, yourColumnName2=yourValue2, ....N where yourCondition;Let us create a table for our examplemysql> create table addWhereClauseDemo -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(30), -> StudentPassword varchar(40) -> ); Query OK, 0 rows affected (0.45 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into addWhereClauseDemo(StudentName, StudentPassword) values('John', 'John123456'); Query OK, 1 row affected (0.14 sec) mysql> insert into addWhereClauseDemo(StudentName, StudentPassword) values('Carol', '99999'); Query OK, 1 row affected (0.24 sec) mysql> insert ...
Read MoreHow to delete everything in a MongoDB database?
You can delete everything in a MongoDB database using dropDatabase() function. The syntax is as follows −use yourDatabaseName; db.dropDatabase();The above syntax will delete everything in a MongoDB database.To delete everything in a MongoDB database, let us first display all the databases from MongoDB. The query is as follows −> show dbsThe following is the output −use yourDatabaseName; admin 0.000GB config 0.000GB flighInformation 0.000GB local 0.000GB sample 0.000GB sampleDemo 0.000GB test 0.003GBNow we will delete everything from the database ‘flightInformation’.First, you need to switch the database to ‘flightInformation’. The query is as follows −> use flighInformation; switched to db flighInformationNow here ...
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