5 Popular PHP Interview Questions (With Example Answers)

PHP is a web-based language of scripts that can be used to generate webpages and apps. With more people and businesses turning to web-based solutions, PHP is an important skill set for an enterprise developer to excel in. In this article, you’ll learn what to expect from PHP interview questions and how you can be better prepared to answer them.

What can you expect from a PHP interview?

If you’re interviewing for a software or web developer role or something similar, your interview could include questions about PHP. At face value, these are geared at ascertaining your knowledge of the resource for creating and running scripts. Because developers need to display creativity, critical thinking and problem-solving, interviewers may prefer responses that show you demonstrate both hard and soft skills required for the role.

This article looks at several technical questions, demonstrating how to appropriately tie in your own skills and experience, where applicable. We use the STAR method for answering each of these interview questions, which stands for Situation, Task, Action and Result. If you master this technique, you’ll be better prepared for any interview questions you receive.

5 Popular PHP Interview Questions (With Example Answers)

What can you expect from a PHP interview?

Common PHP interview questions and example answers

The number of questions you can expect about PHP in your interview depends on the needs of the company and the demands of the specific position. Questions may start with basic foundational information and could get progressively more demanding, such as:

What is PHP?
What is your experience with PHP?
Discuss how PHP is executed.
What are the differences between ECHO and PRINT in PHP?
What is the required operation to pass information from a URL?

What is PHP?

As far as introductory questions go, this is a very basic way to open a line of PHP interview questions. It doesn’t require a long-form answer. To cover the totality of the question, define PHP and talk about what it does.

Example: “PHP is a recursive acronym for Hypertext Preprocessor. It’s a web-based scripting language that executes scripts to create websites and web apps. The syntax resembles Perl or C.”

What is your experience with PHP?

When responding to this question, take the opportunity to expand your explanation of PHP beyond a simple definition by including a practical experience where you used PHP to solve a problem and achieved the desired result. To do this, it may be important to understand some of the benefits of PHP over other languages used when programming online.

PHP is a scripting language, which means it is a series of scripts that can be programmed to do several things upon execution, including coding in other languages that are more end-user friendly. PHP scripts typically execute to create the features of a website or web app. The benefits of PHP are as follows:

It’s open-source. It’s not contingent on manufacturer updates or proprietary limitations.
It’s platform-independent. It doesn’t need a proprietary platform to run.
It’s supported. Many databases support PHP integration; it’s also compatible with common servers.
It’s inexpensive. It’s not costly to develop and maintain.

Example: “When I designed websites for Eagle Printing Company, I was asked to create a portal for online orders. I used PHP scripting language to generate JavaScript. The PHP scripts were programmed to generate JavaScript upon execution, and the JavaScript only had to be accessed by a browser to execute. This made it a good choice for creating frontend features that allowed end-users to shop for products. As a result, the company had a reliable, platform-independent customer portal that helped them increase their sales.”

Discuss how PHP is executed.

This question may seem straightforward at first, but it isn’t that simple. PHP is a scripting language that can be executed in the command line interface. However, it’s also a series of scripts that can generate code that is executed in different ways.

A question like this may be designed to understand the depth of your knowledge on PHP, or how easily you can apply soft skills like problem-solving and critical thinking.

Example: “Traditionally, PHP is executed when the specific file name of the script is used in the command-line interface, or CLI. However, PHP can be used to generate other programming languages like JavaScript. In the case of JavaScript, PHP generates the code, which is executed when it is accessed by a browser.”

What are the differences between ECHO and PRINT in PHP?

When you get a question that asks you the difference between two things, it provides you the opportunity to show you understand the nuances and complexity of whatever systems are being discussed. In this case, it’s ECHO and PRINT functions in PHP, however other comparisons could be made like:

GET vs. PUT
PHP4 vs. PHP5
Require() vs. require_once()
Mysqli_fetch_object() vs. mysqli_fetch_array()
Bitwise And vs. Logical And
For vs. for each

Any or all of these comparisons could turn up in PHP interview questions. Consider going into the interview prepared to talk about the nuance of important features, even if it requires some additional studying.

Example: “ECHO and PRINT are similar functions used to output data to a screen in PHP. ECHO is slightly faster and can take multiple parameters, though it rarely does. ECHO has no return value. PRINT, on the other hand, has a return value of one. That means it can be used in expressions. PRINT supports one argument only.”

What is the required operation to pass information from a URL?

PHP can pass information from one site to the next through the URL. This is convenient for users. For instance, imagine you integrate a social media account with a news website so you can comment under your social media profile. Using PHP, your recognized user info can be passed from page to page via the URL. It also allows marketers to pass tracking information from site to site.

This question seeks a practical response on how to ensure the correct information is passed from site to site. Answering this question tests your technical knowledge of PHP and its important features.

Example: “The operations required to pass information via the URL are htmlspecialchars() and urlencode(). These are used to encode and decode the information that can be passed via URL or form.”

A tip for PHP developers

In some instances, you may be required to take a written test, an online test, or work out a code-related problem on a whiteboard. This is a common practice in development interviews, as it serves to very literally test your practical coding skills.

In some cases, interviewers may provide a code snippet and ask you to fix a specific piece of PHP code. Other iterations of this concept include asking you to write a code snippet, define the output of a given piece of code, list values in a code or otherwise identify a problem.

Example: “The problem in this code is that the value is returning null because one of the arguments is flawed. It’s asking for an array_merge with no array. There’s a simple fix for this. You have to target an array in the second argument.”

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