A query string is the part of URL containing key-value pairs.
The query string is needed when the client request wants to pass some extra information which cannot fit conveniently into a hierarchical path structure of URL.
Based on received key-value pairs as query string the server can fine tune, paginate or filter the response in preparing dynamic pages.
Query String format:
field1=value1&field2=value2&field3=value3
Example
The following example URL request supposedly asks the server to return all users living in the state TX.
