Difference between Session and Query String

Querystring	Session
Querystring is client side state management technique.	Session is server side state management technique.
Querystring data is page specific i.e. can be accessed in that page only.	Session data can be accessed throughout the session.
Querystring data is visible to user and can be seen in browser url.	Session data is not visible to user.
Data is not secured and can be altered hence insensitive data is stored in querystring.	Data is secured hence sensitive data such as user information is stored.
Querystring has constraint of Maxlength.	Session does not have such constraint.
Querystring passed through url like www.abc.com?myparam=12.	Session created in application like Session["mysession"] = somevalue.
Querystring fetched on page like string myvalue = Request.QueryString["myparam"].	Session retrived in application like string myvalue = Session["mysession"].

Difference between Get Method and Post Method

Get	Post
Data retrieved using this is cached by the browser	Data retrieved using this is not cached by the browser
Data is passed through URL.	Data is passed through body.
Data sent using this is visible in URL.	Data sent using this is not visible in URL.
Used to send normal data.	Used to send secured and important data.
There is limit over amount of data that can be sent using Get depends on browsers.	There is no limit over amount of data that can be sent using Post.
This is default method for many browsers.	This is not default method and have to be explicitly defined.
Get method can carry only text data	Post method can carry text as well as binary data.
Get method is faster as compared to Post	Post method is slower as compared to Get