One Commit at a Time ! Series - 7

JAVA

# Create objects inside the same class

class Lamp {

  // stores the value for light
  // true if light is on
  // false if light is off
  boolean isOn;

  // method to turn on the light
  void turnOn() {
    isOn = true;
    System.out.println("Light on? " + isOn);

  }

  public static void main(String[] args) {

    // create an object of Lamp
    Lamp led = new Lamp();

    // access method using object
    led.turnOn();
  }
}

OUTPUT :
Light on? true

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SQL

The SELECT DISTINCT statement is used to return only distinct (unique) values.

In a table, a column may contain several duplicate values - and sometimes you want to list only the unique values.

SELECT DISTINCT Syntax
SELECT DISTINCT column1, column2, ...
FROM table_name;

SELECT DISTINCT Country FROM Customers;

Count Distinct Values
By using the COUNT() function with the DISTINCT keyword, we can count the number of unique countries.

SELECT COUNT(DISTINCT Country) FROM Customers;

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References :
https://www.w3schools.com/sql/sql_distinct.asp
https://www.programiz.com/java-programming/class-objects