MySQL Operators

What Are Operators in MySQL?

An operator is a symbol or keyword that tells MySQL to perform a specific operation on one or more values, called operands. Operators are the backbone of the WHERE clause — without them, you could only ever retrieve entire tables. MySQL groups operators into several families: arithmetic, comparison, logical, and bitwise. This lesson focuses on the two families you will use constantly: comparison operators and logical operators.

Comparison Operators

Comparison operators evaluate two values and return a boolean-like result: 1 (true), 0 (false), or NULL (unknown, when either operand is NULL). They are almost always used inside a WHERE or HAVING clause.

Logical Operators

Logical operators combine multiple boolean expressions into a single condition. MySQL supports AND, OR, NOT, and XOR. Understanding operator precedence matters here: NOT binds tighter than AND, which binds tighter than OR. When mixing AND and OR in the same clause, always use parentheses to make your intent explicit — relying on default precedence is a common source of subtle bugs.

• AND — true only when both sides are true
• OR — true when at least one side is true
• NOT — inverts a boolean expression
• XOR — true when exactly one side is true, but not both

SELECT product_name, price
FROM products
WHERE price BETWEEN 20 AND 80
ORDER BY price;

SELECT customer_name, country, total_spent
FROM customers
WHERE (country = 'US' OR country = 'CA')
  AND total_spent > 500;

SELECT employee_name, department
FROM employees
WHERE department IN ('Sales', 'Marketing')
  AND manager_id IS NOT NULL;

A practical rule of thumb: reach for comparison operators when evaluating a single column against a value or range, and reach for logical operators the moment you need to describe a condition in terms of 'and', 'or', or 'not'. Combining both families fluently is what separates a basic SELECT from a genuinely useful report query.