PHP Developer Interview Questions

This article provides a list of questions designed to assess a PHP developer’s skills in areas like string manipulation, debugging, database handling, and advanced PHP features.

1. What is PHP? Why is PHP a Loosely Typed Language? Is PHP Asynchronous or Synchronous?

2. What is the difference between include, require, include_once, and require_once?

3. Identify the Issues in the Query Below

   "SELECT * FROM users WHERE email = $_POST['email']";

4. Fix the Logical Error in the Statement

   if (!strpos($string, $substring))

5. What is the Value of $x and $y After the Function Call?

   function incrementCounter(&$counter) {
       $initialValue = $counter;
       $counter += 2;
       return $initialValue;
   }
    
   $x = 5;
   $y = incrementCounter($x);

6. Predict the Output of the Following Code and Explain Why?

   $num = 10;
   function modifyNumber() {
       $num = 20;
   }
   modifyNumber();
   echo $num;

7. Predict the Value of $x and Why?

   $octalValue = 017;
   $x = $octalValue / 2;

8. What Will Be the Output?

   $method = "greet";
   function greet() {
       echo "Hello, world!";
   }
   $method();

9. Explain $$var and Its Use Case in PHP. Can It Go Infinitely or Not?

10. Describe Magic Methods in PHP

11. Logical String Manipulation Question

    Write a PHP function that takes a string and:

    • Reverses it.
    • Replaces all vowels (a, e, i, o, u) with their uppercase equivalent.
    • Replaces all consonants with #.

    Example:

    Input: "helloWorld"
    Output: "DLROw#O###"

12. Predict the Output of the Code Below and Explain Why?

    $name = "Sunita";
    echo "Hi, my name is {$name}";
    echo 'Hi, my name is {$name}';