Top PHP Intermediate Interview Questions

Here are 50 intermediate-level interview questions for PHP:

1. What is PHP, and how does it differ from other programming languages?
2. What are the differences between GET and POST methods in PHP?
3. What is an array, and how is it used in PHP?
4. What is the difference between include() and require() in PHP?
5. What is a session in PHP, and how does it work?
6. How would you generate a random number in PHP?
7. What are the different types of loops in PHP, and how are they used?
8. How do you create a function in PHP?
9. What is the difference between echo and print in PHP?
10. What are the different types of variables in PHP, and how are they used?
11. What is the difference between the == and === operators in PHP?
12. How do you connect to a database using PHP?
13. What is a PDO in PHP, and how is it used?
14. What is the difference between mysqli and PDO in PHP?
15. How would you handle errors in PHP?
16. What are namespaces in PHP, and how are they used?
17. What is the difference between abstract and interface classes in PHP?
18. What is the difference between public, private, and protected in PHP?
19. How would you create a singleton class in PHP?
20. What is a trait in PHP, and how is it used?
21. How do you handle exceptions in PHP?
22. What is the difference between isset and empty in PHP?
23. How do you create a regular expression in PHP?
24. What is the difference between preg_match and preg_replace in PHP?
25. How do you create a cookie in PHP?
26. What is the difference between a cookie and a session in PHP?
27. How do you create a file in PHP?
28. How do you read data from a file in PHP?
29. How do you write data to a file in PHP?
30. What is the difference between fopen and file_get_contents in PHP?
31. What is the difference between require_once and include_once in PHP?
32. What is the difference between count() and sizeof() in PHP?
33. How would you create an object in PHP?
34. What is the difference between an object and a class in PHP?
35. How would you create a child class in PHP?
36. What is the difference between an abstract class and an interface in PHP?
37. What is the difference between static and non-static methods in PHP?
38. What is a final class in PHP, and how is it used?
39. How do you declare a constant in PHP?
40. What is a recursive function in PHP, and how is it used?
41. What is the difference between var_dump and print_r in PHP?
42. How do you create a multidimensional array in PHP?
43. What is the difference between array_merge and array_combine in PHP?
44. How do you sort an array in PHP?
45. How do you search for an element in an array in PHP?
46. What is a callback function in PHP, and how is it used?
47. What is the difference between array_map and array_filter in PHP?
48. How do you use the $_SERVER variable in PHP?
49. How do you use the $_REQUEST variable in PHP?
50. What is the difference between the post_max_size and upload_max_filesize directives in PHP.ini?

Good luck with your interview!