A Beginner's Handbook to SQL Operators

 A Beginner's Handbook to SQL Operators

SQL (Structured Query Language) is a standard language used to interact with relational databases. SQL operators are crucial tools within this language, allowing users to perform various operations on the data stored in databases. This handbook covers the basics of SQL operators, providing an introduction to their types and usage.

1. Arithmetic Operators

Arithmetic operators perform mathematical operations on numerical data.

- Addition ('+'): Adds two values.

'''sql

SELECT 5 + 3; -- Result: 8

'''

- Subtraction ('-'): Subtracts one value from another.

'''sql

SELECT 5 - 3; -- Result: 2

'''

- Multiplication (''): Multiplies two values.

'''sql

SELECT 5 3; -- Result: 15

'''

- Division ('/'): Divides one value by another.

'''sql

SELECT 6 / 3; -- Result: 2

'''

- Modulus ('%'): Returns the remainder of a division.

'''sql

SELECT 5 % 3; -- Result: 2

'''

2. Comparison Operators

Comparison operators are used to compare two values. The result is a boolean value ('TRUE' or 'FALSE').

- Equal to ('='): Checks if two values are equal.

'''sql

SELECT FROM employees WHERE age = 30;

'''

- Not equal to ('<>' or '!='): Checks if two values are not equal.

'''sql

SELECT FROM employees WHERE age <> 30;

'''

- Greater than ('>'): Checks if a value is greater than another.

'''sql

SELECT FROM employees WHERE age > 30;

'''

- Less than ('<'): Checks if a value is less than another.

'''sql

SELECT FROM employees WHERE age < 30;

'''

- Greater than or equal to ('>='): Checks if a value is greater than or equal to another.

'''sql

SELECT FROM employees WHERE age >= 30;

'''

- Less than or equal to ('<='): Checks if a value is less than or equal to another.

'''sql

SELECT FROM employees WHERE age <= 30;

'''

3. Logical Operators

Logical operators combine multiple conditions to form complex queries.

- AND: Combines two conditions; both must be true.