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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to select ID column as null in MySQL?
Let us first create a table. The query to create a table is as followsmysql> create table selectAllDemo - > ( - > Name varchar(100), - > Age int - > ); Query OK, 0 rows affected (1.90 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into selectAllDemo values('John', 25); Query OK, 1 row affected (0.99 sec) mysql> insert into selectAllDemo values('Carol', 26); Query OK, 1 row affected (0.42 sec) mysql> insert into selectAllDemo values('Bob', 30); Query OK, 1 row affected (1.57 ...
Read MoreHow to get default phone Network operator name in android?
This example demonstrate about How to get default phone Network operator name in android.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. In the above code, we have taken a text view to show the phone network operator name.Step 3 − Add the following code to java/MainActivity.xmlpackage com.example.myapplication; import android.Manifest; import android.content.Context; import android.content.pm.PackageManager; import android.os.Build; import android.os.Bundle; import android.support.annotation.NonNull; import android.support.annotation.RequiresApi; import android.support.v4.app.ActivityCompat; import android.support.v7.app.AppCompatActivity; import android.telephony.TelephonyManager; import android.widget.TextView; ...
Read MoreLongStream map() method in Java
The map() method of the LongStream class in Java returns a stream consisting of the results of applying the given function to the elements of this stream.The syntax is as follows:LongStream map(LongUnaryOperator mapper)Here, the parameter mapper is a stateless function to apply to each element. The LongUnaryOperator represents an operation on a single long-valued operand that produces a long-valued result.To use the LongStream class in Java, import the following package:import java.util.stream.LongStream;Create a LongStream and add some elements:LongStream longStream1 = LongStream.of(15L, 30L, 45L, 67L, 80L);Now, create another LongStream and map it to a condition set for the elements of longStream1:LongStream longStream2 ...
Read MoreMySQL select order by acts like a string (not a number)?
You can use the following syntax if your column has varchar data type −select yourColumnName FROM yourTableName ORDER BY yourColumnName +0 DESC;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table selectOrderdemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(100), -> RankNumber varchar(100) -> ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into selectOrderdemo(Name, RankNumber) values('Larry', -100); Query OK, 1 row affected (0.23 ...
Read MoreHow to drop constraint on a column of a table in a database using JDBC API?
You can drop a constraint on a column of a table using the ALTER TABLE command.SyntaxALTER TABLE table_name DROP CONSTRAINT MyUniqueConstraint;Assume we have a table named Dispatches in the database with 7 columns namely id, CustomerName, DispatchDate, DeliveryTime, Price and, Location with description as shown below:+--------------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------------+--------------+------+-----+---------+-------+ | ProductName | varchar(255) | YES | UNI | NULL | | | CustomerName | varchar(255) | YES | | NULL | ...
Read MoreMySQL query to retrieve records from the part of a comma-separated list?
To retrieve records from the part of a comma-separated list, you can use built in function FIND_IN_SET().Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Name varchar(20), Marks varchar(200) ); Query OK, 0 rows affected (0.61 sec)Following is the query to insert some records in the table using insert command −mysql> insert into DemoTable(Name, Marks) values('Larry', '98, 34, 56, 89'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable(Name, Marks) values('Chris', '67, 87, 92, 99'); Query OK, 1 row affected (0.15 sec) mysql> insert ...
Read MoreMySQL Merge selects together?
To merge selects together, you need to use GROUP BY clause. To understand the concept, let us create a table. The query to create a table is as follows −mysql> create table MergingSelectDemo -> ( -> RoomServicesId int, -> RoomId int, -> ServiceId int -> ); Query OK, 0 rows affected (1.98 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into MergingSelectDemo values(10, 10, 10); Query OK, 1 row affected (0.29 sec) mysql> insert into MergingSelectDemo values(20, 10, 20); Query OK, 1 row affected ...
Read MoreIs it possible to calculate a correlation in a MySQL query?
Yes, it is possible to calculate a correlation in a query. To understand the correlation in a query, you need to first create a table. The query to create a table is as followsmysql> create table correlationDemo - > ( - > value float not null, - > value2 float not null - > ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table with the help of insert command. The query is as follows to insert records in the tablemysql> insert into correlationDemo values(1, ...
Read MoreWhat is the PHP equivalent of MySQL's UNHEX()?
You can use hex2bin() function since it is the PHP equivalent of MySQL's UNHEX().The syntax is as follows −$anyVariableName = hex2bin("yourHexadecimalValue");To understand the above syntax, let us implement the above syntax in PHP. The PHP code is as follows −$myFirstValue = hex2bin("7777772E4D7953514C4578616D706C652E636F6D"); var_dump($myFirstValue); $mySecondValue=hex2bin("416476616E6365644A617661576974684672616D65776F726B"); echo(''); var_dump($mySecondValue);The snapshot of PHP code is as follows −Here is the snapshot of The output −Here is the MySQL UNHEX() −Case 1 − The query is as follows −mysql> SELECT UNHEX("7777772E4D7953514C4578616D706C652E636F6D");The following is The output −+---------------------------------------------------+ | UNHEX("7777772E4D7953514C4578616D706C652E636F6D") | +---------------------------------------------------+ | www.MySQLExample.com ...
Read MoreHow to copy data from one field to another on every row in MySQL?
To copy data from one field to another on every row, use the UPDATE command.Let us first create a table −mysql> create table DemoTable ( StudentId int, StudentFirstName varchar(20), StudentMarks int default 0 ); Query OK, 0 rows affected (0.49 sec)Following is the query to insert records in the table using insert command −mysql> insert into DemoTable(StudentId, StudentFirstName) values(89, 'Larry'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(StudentId, StudentFirstName) values(35, 'Robert'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable(StudentId, StudentFirstName) values(48, 'Chris'); Query OK, 1 row affected (0.13 sec) ...
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