555 php Interview Questions

  • How can we get the browser properties using PHP?
  • What is the purpose of the following files having extensions 1) .frm 2) .myd 3) .myi? What do these files contain?
  • sorting an array?
  • What is maximum size of a database in MySQL?
  • Give the syntax of Grant and Revoke commands?
  • Explain Normalization concept?
  • How can we find the number of rows in a table using MySQL?
  • How can we find the number of rows in a result set using PHP?
  • How many ways we can we find the current date using MySQL?
  • What are the advantages and disadvantages of Cascading Style Sheets?
  • What type of inheritance that PHP supports?
  • How show an image from mysql?
  • How  group the results of a mysql query?
  • How can increase the performance of MySQL select query?
  • What are the advantages/disadvantages of MySQL and PHP?
  • What is the difference between GROUP BY and ORDER BY in Sql?
  • What is the difference between char and varchar data types?
  • What is the functionality of md5 function in PHP?
  • How can I load data from a text file into a table?
  • How can we know the number of days between two given dates using MySQL?
  • How can we know the number of days between two given dates using PHP?
  • How can we change the name of a column of a table?
  • How can we change the name and data type of a column of a table?
  • What are the differences between drop a table and truncate a table? 
  • How do I sort an array by key?
  • When you want to show some part of a text displayed on an HTML page in red font color, what different possibilities are there to do this? What are the advantages/disadvantages of these methods?
  • When viewing an HTML page in a Browser, the Browser often keeps this page in its cache. What can be possible advantages/disadvantages of page caching? How can you prevent caching of a certain page (please give several alternate solutions)?
  • What are the different methods of passing data or information between two calls of a web page? What are the advantages/disadvantages of these methods?
  • An Apache web server is running on a Linux system. Suddenly, the web server delivers the pages very slow. How could you find out possible reasons for that (when using system commands, please specify their names)?
  • What are the different ways to login to a remote server? Explain the means, advantages and disadvantages?
  • Please give a regular expression (preferably Perl/PREG style), which can be used to identify the URL from within a HTML link tag. Example: The regular expression should match the tag <A HREF=”http://www.yoursite.com/”> and give the URL (”http://www.yoursite.com /”) as a return result. Tags should also be matched if they contain other attributes than the HREF attribute.
  • A select query over a large table runs very slow because of the growing number of entries in that table. What different measures could be taken to improve speed?
  • A company wants to store their invoices in a database. They already have their customers and articles in that database. Both customer and article are each identified by an unique integer value. Please create the SQL statements for creating the necessary table(s) for storing the invoices in a MySQL database. An invoice should hold information like invoice number, customer, date, article(s) and quantity etc.
  • For the database from the previous question, please give an SQL query which returns the invoice number of all invoices which contain the article with the number “1234″. The query should be able to run under a MySQL 4.0 database.
  • How would you backup and restore a big MySQL database? What are the advantages of the approach which you have taken over the others?
  • Create a PHP web script with the following attributes: on start, three HTML form elements are shown: an string input field, a checkbox field, a dropdown/pull down list with 5 elements and a submit button. On submission, the form should be redisplayed (while remaining all options/inputs as the user has selected/entered them). Additionally, the selections/inputs of the user should be displayed in text. Please solve this without the use of any external libraries.
  • What is MIME?
  • What is PEAR in PHP?
  • How can I use the COM components in PHP?
  • How can I load the DLLs dynamically?
  • How many ways we can give the output to a browser?
  • How can we know that a session is started or not?
  • What is the default session time in PHP and how can I change it?
  • What changes I have to done in PHP.ini file for file uploading?
  • What are the differences between MySQL_fetch_array(), MySQL_fetch_object(), MySQL_fetch_row()?
  • How can I set a cron and how can i execute it in Unix, Linux, and windows?
  • Steps for the payment gateway processing?
  • How can I rotate an image?
  • find the longest value in my mysql table?
  • How many ways I can register the variables into session?
  • Explain different types of errors in PHP (i.e. arguments in errorreporting function)?
  • How many ways I can redirect a PHP page?
  • List out different arguments in PHP header function?
  • What type of headers have to add in the mail function in which file a attached?
  • What is the difference between <?PHP and <? And which is preferable?
  • What are the differences between include() and include_once() functions?
  • Describe the importance of database abstraction layers in PHP and database connection?
  • Explain MySQL optimization?
  • How do I order the results of my query?
  • What is the difference between using copy() and move() function in PHP file uploading?
  • What is the difference between Reply-to and Return-path in the headers of a mail function?
  • Explain about Type Juggling in PHP?
  • How do I check for an empty field in a form?
  • How can I get the only name of the current executing file?
  • How can I embed a Java program in PHP file and what changes have to be done in PHP.ini file?
  • How can I find what type of images that the PHP version supports?
  • How can I access information sent through POST on a form?
  • What is the difference between a framework, IDE, CMS, Blog
  •  remove HTML tags from a string?
  • What is the difference between client side validation and server side validation? 
  • How can I add text to an image?
  • What is a static variable within a function?
  • What are key tasks for Php executive?
  • $_ENV and $_SERVER ?
  • Cookies Versus Sessions?
  • What is the use of PEAR in php?
  • What Is a Function?
  • $_GET , $_POST,$_COOKIE??
  • Associative Arrays?
  • magic_quotes_gpc, magic_quotes_runtime?
  • What are the different tables present in mysql?
  • What is SQL Injection?
What are encryption functions in PHP?
ans-CRYPT,MD5

How to create a mysql connection?
mysql_connect(servername,username,password);

<?php
mysql_connect("localhost", "admin", "1admin") or die(mysql_error());
echo "Connected to MySQL<br />";
?>
What is SSL ?
 SSL stands for Secure Sockets Layer.The Secure Sockets Layer (SSL) is a commonly-used protocol for managing the security of a message transmission on the Internet.

 Finding the Current Date and Time?
 ans-
Use strftime( ) or date( ) for a formatted time string:
print strftime('%c');
print date('r');
Mon Aug 12 18:23:45 2002
Mon, 12 Aug 2002 18:23:45 -0400
Use getdate( ) or localtime( ) if you want time parts:
$now_1 = getdate( );
$now_2 = localtime( );
print "$now_1[hours]:$now_1[minutes]:$now_1[seconds]";
print "$now_2[2]:$now_2[1]:$now_2[0]";
18:23:45
18:23:45
 
Finding the Difference of Two Dates? 
ans-
Convert both dates to epoch timestamps and subtract one from the other. Use this code to separate the difference into weeks, days, hours, minutes, and seconds:

$epoch_1 = mktime(19,32,56,5,10,1965);
 $epoch_2 = mktime(4,29,11,11,20,1962);
 $diff_seconds = $epoch_1 - $epoch_2;
$diff_weeks = floor($diff_seconds/604800);


How I can get IP address?
ans-getenv("REMOTE_ADDR");

How to store binary data in MySQL?
ans-Use BLOB data type for the database field.

What is CAPTCHA?
ans-CAPTCHA stands for Completely Automated Public Turing Test to tell Computers and Humans
 Apart. To prevent spammers from using bots to automatically fill out forms,
 CAPTCHA programmers will generate an
image containing distorted images of a string of numbers and letters.

What is the difference between sizeof($array) and count($array)?
ans-sizeof($array) - This function is an alias of count()
count($array) - If you just pass a simple variable instead of an array it will return 1.

What is the difference between the functions unlink and unset?
ans-
unlink is a function for file system handling. It will simply delete the file in context.
unset will set UNSET the
specified variable.
unlink is used to delete a file. unset is used to destroy an earlier declared variable.


What is the difference between echo and print?
ans-
echo displays multiple statements and variables but print only
  print is function it returns a value.

What is the default session time in php?
The default session time in php is until closing of browser