SQL | Arithmetic Operators

Prerequisite: Basic Select statement, Insert into clause, Sql Create Clause, SQL Aliases We can use various Arithmetic Operators on the data stored in the tables. Arithmetic Operators are:

+           [Addition]
-           [Subtraction]
/           [Division]
*           [Multiplication]
%           [Modulus]

Addition (+) :

It is used to perform addition operation on the data items, items include either single column or multiple columns. Implementation:

SELECT employee_id, employee_name, salary, salary + 100
   AS "salary + 100" FROM addition;

Output:

employee_id	employee_name	salary	salary+100
1	alex	25000	25100
2	rr	55000	55100
3	jpm	52000	52100
4	ggshmr	12312	12412

Here we have done addition of 100 to each Employee's salary i.e, addition operation on single column. Let's perform addition of 2 columns:

SELECT employee_id, employee_name, salary, salary + employee_id
   AS "salary + employee_id" FROM addition;

Output:

employee_id	employee_name	salary	salary+employee_id
1	alex	25000	25001
2	rr	55000	55002
3	jpm	52000	52003
4	ggshmr	12312	12316

Here we have done addition of 2 columns with each other i.e, each employee's employee_id is added with its salary.

Subtraction (-) :

It is use to perform subtraction operation on the data items, items include either single column or multiple columns. Implementation:

SELECT employee_id, employee_name, salary, salary - 100
    AS "salary - 100" FROM subtraction;

Output:

employee_id	employee_name	salary	salary-100
12	Finch	15000	14900
22	Peter	25000	24900
32	Warner	5600	5500
42	Watson	90000	89900

Here we have done subtraction of 100 to each Employee's salary i.e, subtraction operation on single column. Let's perform subtraction of 2 columns:

SELECT employee_id, employee_name, salary, salary - employee_id
    AS "salary - employee_id" FROM subtraction;

Output:

employee_id	employee_name	salary	salary - employee_id
12	Finch	15000	14988
22	Peter	25000	24978
32	Warner	5600	5568
42	Watson	90000	89958

Here we have done subtraction of 2 columns with each other i.e, each employee's employee_id is subtracted from its salary. Division (/) : For Division refer this link- Division in SQL

Multiplication (*) :

It is use to perform multiplication of data items. Implementation:

SELECT employee_id, employee_name, salary, salary * 100
    AS "salary * 100" FROM addition;

Output:

employee_id	employee_name	salary	salary * 100
1	Finch	25000	2500000
2	Peter	55000	5500000
3	Warner	52000	5200000
4	Watson	12312	1231200

Here we have done multiplication of 100 to each Employee's salary i.e, multiplication operation on single column. Let's perform multiplication of 2 columns:

SELECT employee_id, employee_name, salary, salary * employee_id
     AS "salary * employee_id" FROM addition;

Output:

employee_id	employee_name	salary	salary * employee_id
1	Finch	25000	25000
2	Peter	55000	110000
3	Warner	52000	156000
4	Watson	12312	49248

Here we have done multiplication of 2 columns with each other i.e, each employee's employee_id is multiplied with its salary.

Modulus ( % ) :

It is use to get remainder when one data is divided by another. Implementation:

SELECT employee_id, employee_name, salary, salary % 25000
    AS "salary % 25000" FROM addition;

Output:

employee_id	employee_name	salary	salary % 25000
1	Finch	25000	0
2	Peter	55000	5000
3	Warner	52000	2000
4	Watson	12312	12312

Here we have done modulus of 100 to each Employee's salary i.e, modulus operation on single column. Let's perform modulus operation between 2 columns:

SELECT employee_id, employee_name, salary, salary % employee_id
    AS "salary % employee_id" FROM addition;

Output:

employee_id	employee_name	salary	salary % employee_id
1	Finch	25000	0
2	Peter	55000	0
3	Warner	52000	1
4	Watson	12312	0

Here we have done modulus of 2 columns with each other i.e, each employee's salary is divided with its id and corresponding remainder is shown. Basically, modulus is use to check whether a number is Even or Odd. Suppose a given number if divided by 2 and gives 1 as remainder, then it is an odd number or if on dividing by 2 and gives 0 as remainder, then it is an even number.

Concept of NULL :

If we perform any arithmetic operation on NULL, then answer is always null. Implementation:

SELECT employee_id, employee_name, salary, type, type + 100
    AS "type+100" FROM addition;

Output:

employee_id	employee_name	salary	type	type + 100
1	Finch	25000	NULL	NULL
2	Peter	55000	NULL	NULL
3	Warner	52000	NULL	NULL
4	Watson	12312	NULL	NULL

Here output always came null, since performing any operation on null will always result in a null value. Note: Make sure that NULL is unavailable, unassigned, unknown. Null is not same as blank space or zero. To get in depth understanding of NULL, refer THIS link.
References: Oracle Docs