What is Google Dork??

A Google dork query, sometimes just referred to as a dork, is a search string that uses advanced search operators to find information that is not readily available on a website.

Google dorking, also known as Google hacking, can return information that is difficult to locate through simple search queries. That description includes information that is not intended for public viewing but that has not been adequately protected.[1]

Reference:

  1. (http://whatis.techtarget.com/definition/Google-dork-query)

You can read how to perform a ethic google dorks and sql injection at here