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Database Articles
Page 392 of 546
Convert NumberLong to String in MongoDB?
In order to convert NumberLong to String in MongoDB, you can use toString() −NumberLong('yourValue').valueOf().toString();To convert NumberLong to String, you can use valueOf() as well −NumberLong('yourValue').valueOf();Let us implement both the above syntaxes.Following is the query to convert NumberLong to String with toString() −> NumberLong('1000').valueOf().toString();This will produce the following output −1000Following is the query to convert NumberLong to Number with valueOf()> NumberLong('1000').valueOf();This will produce the following output −1000
Read MoreDoes Mongo shell treats numbers as float by default.? How can we work it around explicitly?
Yes, Mongo shell treats numbers as float by default. To work it as int or any other type, you need to mention explicitly. You can use NumberInt() for this. The syntax is as follows −var anyVariableName= [NumberInt("yourValue1"), NumberInt("yourValue2"), .....N];Let us implement the above syntax in order to treat numbers as integer only (not float) −> var integerArrayDemo = [NumberInt("50"), NumberInt("60"), NumberInt("70"), NumberInt("90"), NumberInt("40")];Following is the query to display the array value −> printjson(integerArrayDemo);This will produce the following output −[ NumberInt(50), NumberInt(60), NumberInt(70), NumberInt(90), NumberInt(40) ]To display the array value, you can use print() −> ...
Read MoreCheck for Existing Document in MongoDB?
You can use findOne() for this. Following is the syntax −db.yourCollectionName.findOne({yourFieldName: 'yourValue'});Let us create a collection with documents −> db.checkExistingDemo.insertOne({"StudentName":"John"}); { "acknowledged" : true, "insertedId" : ObjectId("5cbdf90dac184d684e3fa265") } > db.checkExistingDemo.insertOne({"StudentName":"Carol"}); { "acknowledged" : true, "insertedId" : ObjectId("5cbdf912ac184d684e3fa266") } > db.checkExistingDemo.insertOne({"StudentName":"Sam"}); { "acknowledged" : true, "insertedId" : ObjectId("5cbdf916ac184d684e3fa267") } > db.checkExistingDemo.insertOne({"StudentName":"Mike"}); { "acknowledged" : true, "insertedId" : ObjectId("5cbdf91bac184d684e3fa268") }Display all documents from a collection with the help of find() method −> db.checkExistingDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cbdf90dac184d684e3fa265"), "StudentName" : "John" } { "_id" : ObjectId("5cbdf912ac184d684e3fa266"), "StudentName" : "Carol" } ...
Read MoreGet attribute list from MongoDB object?
To get attribute list from MongoDB object, you can use for loop to extract key and value for document. Let us create a collection with documents −>db.getAttributeListDemo.insertOne({"StudentId":101, "StudentName":"John", "StudentAdmissi onDate":new ISODate('2019-01-12'), "StudentSUbjects":["MongoDB", "Java", "MySQL"]}); { "acknowledged" : true, "insertedId" : ObjectId("5cbdfcc9ac184d684e3fa269") }Display all documents from a collection with the help of find() method −> db.getAttributeListDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cbdfcc9ac184d684e3fa269"), "StudentId" : 101, "StudentName" : "John", "StudentAdmissionDate" : ISODate("2019-01-12T00:00:00Z"), "StudentSUbjects" : [ "MongoDB", "Java", "MySQL" ] }Following is the ...
Read MoreFind size of text stored in a specific MySQL column?
You can use length() from MySQL to find the size of text stores in a specific column. Let us first create a tablemysql> create table DemoTable ( CustomerName longtext ); Query OK, 0 rows affected (0.67 sec)Insert records in the table using insert command −mysql> insert into DemoTable values('Robert'); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output−+--------------+ | CustomerName | +--------------+ | Robert | +--------------+ 1 row in set (0.00 sec)Here is the query to find the size ...
Read MoreIs there a MAX function for rows and not for columns in MySQL?
Yes, you can use GREATEST() from MySQL to check maximum from rows (not columns). Let us first create a table −mysql> create table DemoTable ( Value1 int, Value2 int, Value3 int ); Query OK, 0 rows affected (0.58 sec)Insert records in the table using insert command −mysql> insert into DemoTable values(190, 395, 322); Query OK, 1 row affected (0.16 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output−+--------+--------+--------+ | Value1 | Value2 | Value3 | +--------+--------+--------+ | 190 | 395 ...
Read MoreAdd data to existing data in a MySQL Database?
You can use CONCAT() function for this. Let us first create a table −mysql> create table DemoTable ( UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, UserName varchar(100) ); Query OK, 0 rows affected (0.43 sec)Insert records in the table using insert command −mysql> insert into DemoTable(UserName) values('John'); Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable(UserName) values('Chris'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable(UserName) values('Robert'); Query OK, 1 row affected (0.11 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+--------+----------+ ...
Read MoreHow do you fill in or pad a column with zeros using a MySQL query?
You can use ZEROFILL for column to fill in or pad with zeros. Let us first create a table−mysql> create table DemoTable ( Number int ); Query OK, 0 rows affected (0.58 sec)Following is the query to add zerofill attribute for Number column−mysql> alter table DemoTable change Number Number int(10) zerofill not null; Query OK, 0 rows affected (1.13 sec) Records: 0 Duplicates: 0 Warnings: 0Insert records in the table using insert command −mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values(12); Query OK, 1 row affected (0.53 sec) ...
Read MoreSelect last day of current year in MySQL?
In order to get last day of current year, you can use LAST_DAY() from MySQL. The syntax is as follows−SELECT LAST_DAY(DATE_ADD(CURDATE(), INTERVAL 12-MONTH(CURDATE()) MONTH));Let us implement the above syntax to know the last day of current year−mysql> SELECT LAST_DAY(DATE_ADD(CURDATE(), INTERVAL 12-MONTH(CURDATE()) MONTH));This will produce the following output −+-------------------------------------------------------------------+ | LAST_DAY(DATE_ADD(CURDATE(), INTERVAL 12-MONTH(CURDATE()) MONTH)) | +-------------------------------------------------------------------+ | 2019-12-31 | +-------------------------------------------------------------------+ 1 row in set (0.00 sec)
Read MoreHow do I exclude a specific record in MySQL?
You can exclude a specific record in SQL using not equal to operator(!=). Let us first create a table−mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, ClientName varchar(20), ClientCountryName varchar(10) ); Query OK, 0 rows affected (0.64 sec)Insert records in the table using insert command −mysql> insert into DemoTable(ClientName, ClientCountryName) values('John', 'US'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(ClientName, ClientCountryName) values('David', 'AUS'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable(ClientName, ClientCountryName) values('Mike', 'UK'); Query OK, 1 row affected (0.14 sec)Display all records from the ...
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