PHP interview questions

Review short answers, detailed answers, practical code and common mistakes.

1. How would you explain PHP Introduction in PHP during an interview?beginner

PHP Introduction is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem php introduction solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

<?php
$lesson = "PHP Introduction";
$checklist = ["understand", "run", "change", "explain"];
echo $lesson . ": " . implode(" -> ", $checklist);

2. How would you explain PHP Syntax in PHP during an interview?beginner

PHP Syntax is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem php syntax solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

3. How would you explain Variables and Constants in PHP during an interview?beginner

Variables and Constants is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem variables and constants solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

4. How would you explain Data Types in PHP during an interview?beginner

Data Types is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem data types solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

<?php
$lesson = "Data Types";
$checklist = ["understand", "run", "change", "explain"];
echo $lesson . ": " . implode(" -> ", $checklist);

5. How would you explain Operators in PHP during an interview?beginner

Operators is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem operators solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

6. How would you explain Conditional Statements in PHP during an interview?beginner

Conditional Statements is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem conditional statements solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

7. How would you explain Loops in PHP during an interview?beginner

Loops is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem loops solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

<?php
$lesson = "Loops";
$checklist = ["understand", "run", "change", "explain"];
echo $lesson . ": " . implode(" -> ", $checklist);

8. How would you explain Functions in PHP during an interview?beginner

Functions is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem functions solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

9. How would you explain Arrays Basics in PHP during an interview?beginner

Arrays Basics is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem arrays basics solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

10. How would you explain Array Methods in PHP during an interview?beginner

Array Methods is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem array methods solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

<?php
$lesson = "Array Methods";
$checklist = ["understand", "run", "change", "explain"];
echo $lesson . ": " . implode(" -> ", $checklist);

11. How would you explain String Functions in PHP during an interview?intermediate

String Functions is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem string functions solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

12. How would you explain Superglobals in PHP during an interview?intermediate

Superglobals is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem superglobals solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

13. How would you explain Form Handling GET and POST in PHP during an interview?intermediate

Form Handling GET and POST is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem form handling get and post solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
  $email = htmlspecialchars($_POST["email"]);
  echo "Receipt sent to " . $email;
}

14. How would you explain Form Validation in PHP during an interview?intermediate

Form Validation is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem form validation solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

15. How would you explain PHP Sessions in PHP during an interview?intermediate

PHP Sessions is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem php sessions solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

16. How would you explain PHP Cookies in PHP during an interview?intermediate

PHP Cookies is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem php cookies solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

<?php
session_start();
$_SESSION["user_id"] = 42;
$_SESSION["plan"] = "Pro";
echo "Session initiated for customer ID: " . $_SESSION["user_id"];

17. How would you explain File Handling in PHP during an interview?intermediate

File Handling is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem file handling solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

18. How would you explain File Uploading in PHP during an interview?intermediate

File Uploading is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem file uploading solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

19. How would you explain Error Handling in PHP during an interview?intermediate

Error Handling is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem error handling solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

<?php
$lesson = "Error Handling";
$checklist = ["understand", "run", "change", "explain"];
echo $lesson . ": " . implode(" -> ", $checklist);

20. How would you explain Object Oriented PHP in PHP during an interview?intermediate

Object Oriented PHP is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem object oriented php solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

21. How would you explain Classes and Objects in PHP during an interview?advanced

Classes and Objects is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem classes and objects solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

22. How would you explain Inheritance in PHP during an interview?advanced

Inheritance is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem inheritance solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

<?php
$lesson = "Inheritance";
$checklist = ["understand", "run", "change", "explain"];
echo $lesson . ": " . implode(" -> ", $checklist);

23. How would you explain Interfaces and Abstract Classes in PHP during an interview?advanced

Interfaces and Abstract Classes is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem interfaces and abstract classes solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

24. How would you explain Namespaces in PHP during an interview?advanced

Namespaces is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem namespaces solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

25. How would you explain Composer Package Manager in PHP during an interview?advanced

Composer Package Manager is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem composer package manager solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

<?php
$lesson = "Composer Package Manager";
$checklist = ["understand", "run", "change", "explain"];
echo $lesson . ": " . implode(" -> ", $checklist);

26. How would you explain MySQL Database Connection in PHP during an interview?advanced

MySQL Database Connection is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem mysql database connection solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

27. How would you explain PDO Prepared Statements in PHP during an interview?advanced

PDO Prepared Statements is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem pdo prepared statements solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

28. How would you explain CRUD Operations in PHP during an interview?advanced

CRUD Operations is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem crud operations solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

<?php
$lesson = "CRUD Operations";
$checklist = ["understand", "run", "change", "explain"];
echo $lesson . ": " . implode(" -> ", $checklist);

29. How would you explain PHP Best Practices in PHP during an interview?advanced

PHP Best Practices is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem php best practices solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

30. How would you explain PHP Review in PHP during an interview?advanced

PHP Review is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem php review solves in PHP. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.