One Commit at a Time ! Series - 6

JAVA

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); } // method to turnoff the light void turnOff() { isOn = false; System.out.println("Light on? " + isOn); } } public class Main { public static void main(String[] args) { // create objects led and halogen Lamp led = new Lamp(); Lamp halogen = new Lamp(); // turn on the light by // calling method turnOn() led.turnOn(); // turn off the light by // calling method turnOff() halogen.turnOff(); } } 

SQL

SELECT - extracts data from a database
UPDATE - updates data in a database
DELETE - deletes data from a database
INSERT INTO - inserts new data into a database
CREATE DATABASE - creates a new database
ALTER DATABASE - modifies a database
CREATE TABLE - creates a new table
ALTER TABLE - modifies a table
DROP TABLE - deletes a table
CREATE INDEX - creates an index (search key)
DROP INDEX - deletes an index

The most commonly used SQL aggregate functions are:

MIN() - returns the smallest value of a column
MAX() - returns the largest value of a column
COUNT() - returns the number of rows in a set
SUM() - returns the sum of a numerical column
AVG() - returns the average value of a numerical column
Aggregate functions ignore null values (except for COUNT(*)).

References :

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