1. What is PHP?

PHP (Hypertext Preprocessor) is a widely-used, open-source scripting language suited for web development. It runs on the server side and helps generate dynamic web pages.

2. What are the key features of PHP?

• Open-source and free to use
• Cross-platform compatibility
• Supports databases like MySQL, PostgreSQL, and SQLite
• Simple syntax, easy to integrate with HTML
• Supports Object-Oriented Programming (OOP)

3. What is the difference between echo and print in PHP?

Both echo and print are used to output data, but:

• echo can take multiple parameters and is slightly faster.
• print returns a value (1), so it can be used in expressions.

4. How do you declare variables in PHP?

PHP variables start with a $ sign:

• $name = “John Doe”;
• $age = 30;
• Variables in PHP are case-sensitive.

Intermediate PHP Interview Questions

5. What are super global variables in PHP?

Super global variables are built-in PHP arrays that provide information from server, session, and user input.

Examples include:

• $_GET – Retrieves data from URL parameters
• $_POST – Collects form data
• $_SESSION – Stores session variables
• $_COOKIE – Handles user cookies
• $_SERVER – Provides server information

6. What is the difference between include and require?

• include – Includes a file, but if the file is missing, it will throw a warning and continue execution.
• require – Includes a file, but if the file is missing, it will throw a fatal error and halt execution.

7. How does PHP handle errors?

PHP offers various error handling methods:

• error_reporting(E_ALL); – Displays all errors.
• try-catch blocks – Used for exception handling.
• set_error_handler() – Custom error handlers.

8. What is the use of explode() and implode() in PHP?

• explode(delimiter, string) – Splits a string into an array.
• implode(delimiter, array) – Joins array elements into a string.

Example:

• $str = “apple,banana,orange”;
• $fruits = explode(“,”, $str);

Advanced PHP Interview Questions

9. What is a PHP session?

A session allows data storage across multiple pages.

• session_start();
• $_SESSION[‘username’] = “JohnDoe”;

Sessions are stored on the server and persist until the browser is closed or manually destroyed.

10. What is Composer in PHP?

• Composer is a dependency manager for PHP. It helps install and manage external libraries.
• composer require monolog/monolog

11. How does PHP interact with databases?

• PHP connects to databases using MySQLi or PDO.
• $conn = new mysqli(“localhost”, “username”, “password”, “database”);
• PDO is more secure and recommended for database interactions.