http://www.phpandsql.com/blog/why-we-use-query-string-in-php/ Query string is a bunch of characters input to a PC or web browser.

3.  What Is Query String In Php
 What Is String Function In Php
 What Is The Size Limit Of String In Php
 What Is Mysql_real_escape_string
Function In Php

5.  Query string is a bunch of characters input to a PC
or web browser & forward to a query program to
pick up detailed information from a database. On
Internet, a query string is division of the bunch of
characters automatically input in the ‘address bar’
of a dynamic website when a user forms a request
for detail according to definite criteria.

6.  www.phpandsql.com/blog/why-we-use-
query-string-in-php/