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You can use aggregate function sum() inside COALESCE(). The below syntax returns the sum of all if the record exists otherwise 0 is returned. The syntax is as follows.select COALESCE(sum(yourColumnName2), 0) AS anyVariableName from yourTableName where yourColumnName1 like '%yourValue%';To understand the above syntax, let us create a table. The query to create a table is as follows.mysql> create table SumDemo -> ( -> Words varchar(100), -> Counter int -> ); Query OK, 0 rows affected (0.93 sec)Insert some records in the table using insert command. The query is as follows.mysql> insert into SumDemo values('Are You There', 10); Query OK, 1 ... Read More
The super keyword in Java is a reference to the object of the parent/superclass. Using it, you can refer/call a field, a method or, a constructor of the immediate superclass.Referring to a field using super keywordAs mentioned above, you can refer to an instance filed/variable of the immediate superclass from an instance method or, a constructor of a subclass, using the "super" keyword.If a class extends another class, a copy of members of the parent class will be created in the subclass i.e. Using the object of the subclass you can access the members of both subclass and the superclass.If ... Read More
The "this" keyword in Java is used as a reference to the current object, within an instance method or a constructor. Using it, you can refer the members of a class such as constructors, variables, and methods.Assigning reference to "this"According to the definition "this" is a keyword which acts as a reference to the current object (the object from whose constructor/method you are using it), its value id is fixed. Therefore, you cannot assign a new reference value to it. Moreover, it is just a keyword, not a variable.Still, if you try to it assign a reference value to "this" it ... Read More
The "this" keyword in Java is used as a reference to the current object, within an instance method or a constructor. Using this you can refer the members of a class such as constructors, variables, and methods.Returning “this”Yes, you can return this in Java i.e. The following statement is valid.return this;When you return "this" from a method the current object will be returned.ExampleIn the following Java example, the class Student has two private variables name and age. From a method setValues() we are reading values from user and assigning them to these (instance) variables and returning the current object.public class Student ... Read More
First, create a user and password using CREATE command. The syntax is as follows.CREATE USER 'yourUserName'@'localhost' IDENTIFIED BY 'yourPassword';The syntax to give all privileges of the specific database to the user is as follows.GRANT ALL PRIVILEGES ON yourDatabaseName . * TO 'yourUserName'@'localhost';Now you can implement the above syntaxes to create a user and grant all privileges.Step 1 − Create a userThe query is as follows.mysql> create user 'Adam Smith'@'localhost' IDENTIFIED BY 'Adam123456'; Query OK, 0 rows affected (0.29 sec)Step 2 − Grant all privileges to the user.The query is as follows.mysql> GRANT ALL PRIVILEGES ON test . * TO 'Adam ... Read More
You can do this with the help of information_schema.tables. The syntax is as follows -SELECT TABLE_NAME, table_rows, data_length, index_length, round(((data_length + index_length) / 1024 / 1024), 2) "MB Size" FROM information_schema.TABLES WHERE table_schema = "yourDatabaseName" ORDER BY (data_length + index_length) ASC;To understand the above syntax, let us implement it for any database. Here, I am using database TEST. Let us see the query for our database TEST.mysql> SELECT TABLE_NAME, table_rows, data_length, index_length, -> round(((data_length + index_length) / 1024 / 1024), 2) "MB Size" -> FROM information_schema.TABLES WHERE table_schema = "test" -> ORDER BY (data_length + index_length) ASC;The following is the ... Read More
This example demonstrate about How to get volley array list with custom object 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 text view to show custom array list object elements.Step 3 − Add the following code to src/MainActivity.javapackage com.example.myapplication; import android.os.Build; import android.os.Bundle; import android.support.annotation.RequiresApi; import android.support.v7.app.AppCompatActivity; import android.util.Log; import android.widget.TextView; import com.android.volley.Request; import com.android.volley.RequestQueue; import com.android.volley.Response; import com.android.volley.VolleyError; import com.android.volley.toolbox.StringRequest; import com.android.volley.toolbox.Volley; ... Read More
An exception is a problem that arised during the execution of a program. During the execution of a program when an exception occurs, code following the statement will not be executed, and PHP will attempt to find the first matching catch block. If an exception is not caught, a PHP Fatal Error will be issued with an “Uncaught Exception”.Syntax try { print "this is our try block"; throw new Exception(); }catch (Exception $e) { print "something went wrong, caught yah! n"; }finally { ... Read More
This example demonstrate about How to get volley elements in array list 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 text view to show volley elements.Step 3 − Add the following code to src/MainActivity.javapackage com.example.myapplication; import android.os.Build; import android.os.Bundle; import android.support.annotation.RequiresApi; import android.support.v7.app.AppCompatActivity; import android.util.Log; import android.widget.TextView; import android.widget.Toast; import com.android.volley.Request; import com.android.volley.RequestQueue; import com.android.volley.Response; import com.android.volley.VolleyError; import com.android.volley.toolbox.StringRequest; import com.android.volley.toolbox.Volley; import org.json.JSONArray; import ... Read More
A persistent cookie is a cookie that is stored in a cookie file permanently on the browser's computer. As we know cookies are small text files which are as a matter, of course, temporary cookies which stored only in the browser's memory. When the browser is closed, temporary cookies will be erased from the memory.When to use persistent cookies −Temporary cookies can not be used for tracking long-term information.Persistent cookies can be used for tracking long-term information.Temporary cookies are safer because no programs other than the browser can access them.Persistent cookies are less secure because users can open cookie files ... Read More