? MySQL AND, OR, NOT Operators

? Quick Overview

MySQL logical operators AND, OR, and NOT are used inside the WHERE clause to filter records based on multiple conditions. They are heavily used in PHP-driven applications where dynamic queries are required.

? Key Concepts

AND → All conditions must be true
OR → At least one condition must be true
NOT → Excludes matching records
Parentheses control evaluation order

? Syntax / Theory

Logical operators are combined inside the WHERE clause. MySQL evaluates AND before OR unless parentheses are used.

? AND Operator

? View Code Example

// Select users older than 30 AND living in New York
SELECT * FROM users
WHERE age > 30 AND city = 'New York';

⚡ OR Operator

? View Code Example

// Select users older than 30 OR living in New York
SELECT * FROM users
WHERE age > 30 OR city = 'New York';

❌ NOT Operator

? View Code Example

// Exclude users who live in New York
SELECT * FROM users
WHERE NOT city = 'New York';

? Combining AND, OR, and NOT

? View Code Example

// Combine OR with AND and exclude inactive users
SELECT * FROM users
WHERE (age > 30 OR city = 'New York') AND NOT status = 'inactive';

?️ Example: Using Multiple Operators

? View Code Example

// Filter users by city, age, and active status
SELECT * FROM users
WHERE (city = 'Chicago' OR city = 'Houston')
AND age > 25
AND NOT status = 'inactive';

? Live Explanation

The database evaluates grouped conditions first. Records are returned only when all final logical expressions resolve to true. This logic is commonly used in PHP-backed dashboards, admin panels, and reports.

? Visual Logic Diagram

? Use Cases

User filtering in PHP + MySQL applications
Search functionality with multiple conditions
Admin dashboards and reports
Access control and role-based queries

✅ Tips & Best Practices

Always use parentheses when mixing AND and OR
Write readable conditions for maintainability
Test queries directly in MySQL before embedding in PHP
Use prepared statements in PHP for safety

? Try It Yourself

Fetch users from Los Angeles or age above 25
Retrieve users not from New York or Los Angeles
Filter users younger than 30 and not active
Create a custom query combining all three operators