? MySQL SELECT With WHERE Clause

? Quick Overview

The WHERE clause in MySQL is used to filter records that meet a specific condition. It is commonly used with SELECT queries in PHP-MySQL applications to retrieve only the required data.

? Key Concepts

Filters rows based on conditions
Used with comparison and logical operators
Essential for dynamic PHP database queries

⚡ Syntax / Theory

? View Code Example

// Basic SELECT query with WHERE condition
SELECT column1, column2
FROM table_name
WHERE condition;

? Example 1: Filter Records

? View Code Example

// Fetch users older than 30
SELECT * FROM users
WHERE age > 30;

? Explanation

Only users whose age value is greater than 30 will be returned from the database.

? Example 2: WHERE with AND / OR

? View Code Example

// Multiple conditions using AND
SELECT * FROM users
WHERE age > 30 AND city = 'New York';

? View Code Example

// Either condition using OR
SELECT * FROM users
WHERE age > 30 OR city = 'New York';

? Example 3: WHERE with LIKE

? View Code Example

// Pattern matching using LIKE
SELECT * FROM users
WHERE username LIKE 'J%';

?️ Example 4: WHERE with IN

? View Code Example

// Filter using multiple values
SELECT * FROM users
WHERE city IN ('New York','Los Angeles');

? Interactive Understanding

Imagine a PHP login page that only fetches users with a matching email. The WHERE clause makes this possible efficiently.

? Use Cases

User authentication in PHP
Filtering search results
Admin dashboards and reports
Dynamic API responses

✅ Tips & Best Practices

Always sanitize user input in PHP
Use indexed columns for faster WHERE queries
Prefer prepared statements for security

? Try It Yourself

Select users older than 25 from Los Angeles
Find emails containing the word "example"
Combine AND and OR for advanced filters