Operators
=========
-> Operator is a symbol
which can denote the operation.

Ex: totalSalary = basicSalary + bonus

1) Arithmetic operators:
========================
+, -, *, /

=> for performing calculations in SQL queries like: select, update, insert etc.

Q: Write a query to create employees table with the given fields:
	1) employeeID
	2) name
	3) basic_salary
	4) bonus
insert the data according to the given columns
q-1: Display/retrieve the employees details with id, name, basic salary, bonus and total salary.

create table AshokIt_Employees1
(
    employeeId varchar2(15) primary key,
    name varchar(50) null,
    basic_Salary decimal(10,2) null,
    bonus decimal(10,2)
);

insert into AshokIt_Employees1 (employeeId,name,basic_Salary,bonus)
values('AIT192937','Ajith',22500,12500);

insert into AshokIt_Employees1 (employeeId,name,basic_Salary,bonus)
values('AIT912997','Akhila',27500,15200);

insert into AshokIt_Employees1 (employeeId,name,basic_Salary,bonus)
values('AIT998937','Ashok',75000,35000);

insert into AshokIt_Employees1 (employeeId,name,basic_Salary,bonus)
values('AIT199237','Anusha',32500,12500);

select * from AshokIt_Employees1;

select employeeId,
name,
basic_Salary,
bonus,
basic_Salary + bonus as total_Salary
from AshokIt_Employees1;

============================================
q-2: Write a query to display/retrieve id, name, basic_Salary, bonus, tax, net_Salary from employees.

select employeeId,
name,
basic_Salary,
bonus,
basic_Salary * 0.1 as tax,
basic_Salary - (basic_Salary * 0.1) as net_Salary
from AshokIt_Employees1;

Assignment:
-----------
1) Write a query to make report with the data of employees whose total_salary is above and equals to 100000;

How to use arithmetic operators in update statement:
====================================================
Ex-1:
-----
update AshokIt_Employees1
set bonus = basic_Salary * 0.15;

select * from ashokit_employees1;

Ex-2:
----
update ashokit_employees1 set basic_salary = basic_salary * 1.05;

select * from ashokit_employees1;

How to use arithmetic operations in insertion:
==============================================

create table products1012
(
    product_Id int,
    price decimal(10,2),
    tax decimal(7,2),
    total_price decimal(10,2)
);

insert into products1012(product_Id,price,tax,total_price)
values(1020331,999,999 * 0.18,999 + (999 * 0.18));

insert into products1012(product_Id,price,tax,total_price)
values(1122331,1999,1999 * 0.18,1999 + (1999 * 0.18));

select * from products1012;

Q: Write a query to prepare the report with employee details whose mail id is null.

create table XYZ_Employees
(
    empId int,
    empName varchar(50),
    basic_salary decimal(10,2),
    designation varchar2(30),
    mail varchar2(100)
);

insert into XYZ_Employees values(10293847,'Abhishek',65000,'SQL Developer','abhishke123@xyz.com');

insert into XYZ_Employees values(11293747,'Archana',55000,'Python Developer','archana1929@xyz.com');
insert into XYZ_Employees values(12393847,'Kalyani',35000,'Java Developer','kayani123@xyz.com');
insert into XYZ_Employees values(10203040,'Ashok',75000,'Java Developer','ashok1199@xyz.com');
insert into XYZ_Employees values(11213141,'Keerthi',65000,'SQL Developer',null);
insert into XYZ_Employees values(19293949,'Alekhya',85000,'Python Developer',null);

select * from XYZ_Employees;

select empId,empName from XYZ_Employees
where mail is null;

Note:
----
In SQL, we have:
	= ===> equal to
	!= or <> ==> not equal to
	>, <, >=, <=, 
	is null
	is not null
are comparison operators.