- PHP Tutorial
- PHP Syntax
- PHP Variables
- PHP Data Types
- PHP Constants
- PHP Operators
- PHP if elseif else statements
- PHP Switch Statement
- Arrays in PHP
- Loops in PHP
- Strings in PHP
- GET and POST in PHP
- Functions in PHP
- Cookies in PHP
- Sessions in PHP
- Include and Require in PHP
- File Opening and Reading in PHP
- File Creation and Writing in PHP
- Form Validation in PHP
- Date and Time Functions in PHP
- Validation and Sanitizing Data Via PHP Filters
- Introduction to Object Oriented Programming in PHP
- Parameterized Constructors in PHP
- Inheritance in Object Oriented PHP
- Abstract Class in PHP
- Math Functions in PHP
- Error and Exception Handling in PHP
- Reading XML data in PHP
- Reading XML Nodes/Attributes Values in PHP
- XML DOM Parser
- Sorting Arrays in PHP
- Commonly Used Array Functions in PHP
- Commonly Used String Functions in PHP
- Access Modifiers in PHP
- Variable Examination Functions in PHP
- File Upload in PHP
- PHP and AJAX
- PHP Frameworks
- Connecting PHP to MySQL
- Create Database in MySQL via PHP Script
- Drop Database in MySQL via PHP Script
- Selecting Mysql Database via PHP Script
- Create Table in MySQL via PHP Script
- Drop Table in MySQL
- Inserting Data in MySQL Table via PHP Script
- Selecting MySQL Table Data via PHP Script
- Where Clause in MySQL
- Update MySQL Table data via PHP Script
- Deleting Data From MySQL Table via PHP Script
- Sorting MySQL table data via PHP Script
- LIKE Query in MySQL
- Select Unique Data via Distinct In MySQL
- IN Operator in MySQL
- Using BETWEEN operator in MySQL
- AND/OR Operators In MySQL
- Selecting Limited records via LIMIT in MySQL
- Max and Min Functions in MySQL
- SUM and AVG Functions in MySQL
- Using COUNT Function in MySQL
- UCASE and LCASE Functions in MySQL
- GROUP BY and HAVING Clauses in MySQL
- INSERT INTO SELECT in MySQL
- DEFAULT Statement in MySQL
- Implementing Check on Table Columns
- INNER JOIN in MySQL
- LEFT JOIN in MySQL
- RIGHT JOIN In MySQL
- Implementing FULL Join in MySQL
PHP Syntax
PHP script can be written anywhere inside a HTML document. It can be inserted between HTML or JavaScript tags.
PHP tags
The most commonly used PHP tag style starts with <?php and ends with ?>
<?php // Block of PHP code ?>
Short-open tags
If you are using short-open tags then ensure short_open_tag is enabled and set to ON in configuration file php.ini.
<? // Block of PHP code ?>
Comments in PHP code
Comments are used to describe the code, which is only intended to be read by human beings. Comments do not get compiled or executed. The purpose of comments is to help others understand or remind you later what has been implemented and the purpose of the block of code. There are two types of comments in PHP
- Single-line Comment
- Multi-line Comment
<?php
// This is an example of single-line comment.
/*
This is an example of multi-line comment
Which covers multiple lines
*/
?>Download the code Run the code
Case sensitivity
- The keywords (like if, while, for, echo, etc.), function names and classes are NOT case sensitive in PHP.
- Variable names ARE case sensitive.
Let’s look at the below example, where all the usage of echo is correct.
<?php
echo "Welcome to the world of PHP<br>";
ECHO "Welcome to the world of PHP<br>";
eCHo "Welcome to the world of PHP<br>";
?>Download the code Run the code
Now, in the below example, variable name is case-sensitive and displays the value of first echo statement only.
<?php
$KH_Name = "John";
echo "My name is " . $KH_Name . "<br>"; // Output: My name is John
echo "My name is " . $KH_NAME . "<br>"; // Output: Notice: Undefined variable: KH_NAME
echo "My name is " . $kh_name . "<br>"; // Output: Notice: Undefined variable: kh_name
?>Download the code Run the code
Statement termination by semicolons
In PHP, any statement which is an expression, is terminated by semicolon (;). In the above example, each echo statement is terminated with a semicolon.