There are following types of engines available in the mysql.

1. MyISAM

2. Heap

3. ISAM

4. InnoDB

5. Merge

6. BDB

You can get the 3rd maximum salary as :

SELECT MIN(Emp_Salary) FROM Salary WHERE Emp_Salary IN(SELECT TOP 3 Emp_Salary FROM Salary ORDER BY Emp_Salary DESC)

It compresses the MYSQL MyISAM tables

You can get the current session id using :

session_id()

If you delete the cookie of the browser the session will destroy because session id is stored on client’s browser and session value is stored on the server.

You can store as the unlimited data within in sessions. All sessions are stored on the server on hard disk. But by default the maximum_memory limit is 128 M. If you want to store more data increase the memory limit.

Default time for the Php sesssion is untill the browser is closed.

What is PEAR in php?

PEAR stands PHP Extension and Application Repository is a framework and repository for reusable PHP components.
The PEAR Packages include functionality providing for authentication, networking, and file system functionality.
PEAR is a code repository containing libraries and snippets.

What are types of errors in PHP??

1. Notices.
2. Warnings.
3. Fatal Errors.