PHP WEB DEVELOPMENT PART - 1 PROBABLE MOST IMPORTANT INTERVIEW QUESTIONS AND ANSWERS MADE BY ME GENERALLY ASKED IN PITANGENT ANALYTICS AND TECHNOLOGY SOLUTIONS PVT. LTD. FOR FRESHERS

PHP WEB DEVELOPMENT PART - 1 PROBABLE MOST IMPORTANT INTERVIEW QUESTIONS AND ANSWERS MADE BY ME GENERALLY ASKED IN PITANGENT ANALYTICS AND TECHNOLOGY SOLUTIONS PVT. LTD. FOR FRESHERS

Q1. What is the difference between == and ===?

Ans: == -> This operator is used to check whether the given values are equal or not. If yes, it returns true, otherwise it returns false.

=== -> This operator is used to check whether the given values and it's data types are equal or not.

Q2. What are superglobals in PHP?

Ans: Superglobals in PHP are the pre-defined global variables. All superglobal variables are written in capital letters. For ex. : $_GLOBALS, $_GET, $_POST, $_COOKIES, $_SESSION, $_REQUEST, $_FILES, etc.

Q3. What are variables and constants in PHP?

Ans: Variables = Variables are containers for storing information. A variable start with the $ sign, followed by the name of the variable. For ex. : $x=10; $y="Capgemini";

Constants = Constants are like variables, except that once they are defined they cannot be changed or undefined. Syntax : define(name, value);

For ex. : define("GREETING","Welcome to Capgemini.com");

               echo "GREETING";

Q4. What is the difference between echo, print and print_r().

Ans: 

echo => echo returns void i.e. it doesn't return any values. echo  speed is fastest.

print => print returns 1 on success. print speed is slightly slower.

print_r() => print_r() returns data as string if the 2nd argument is true. print_r() speed is slower for debugging.

Q5. Write a SQL query to fetch employees with salary greater than 50,000.

Ans: SELECT * FROM `employees` WHERE salary>50000;

Q6. Write a SQL query to get the top 3 departments with the highest number of employees.

Ans: SELECT department, COUNT(*) AS employee_count FROM `employees` GROUP BY department ORDER BY employee_count DESC LIMIT 3;

Q7. Write a query to join two tables users and orders where user ID matches.

Ans: SELECT * FROM `users` JOIN `orders` ON users.user_id=orders.user_id;    `