In this thread I am going to be teaching to you how Dorks work
Example:
Take this as the dork we are going to be "looking" at: "inurl:buy.php?id="
Explanation:
What the "inurl": simply means that it will search for in the URL (hence inurl)so it will search whatever you put in it. So now the PHP. Just think it of a PHP file that can have a parameter of - so for example "category id" which is "cat_id". All you have to do is type "inurl" and after for example categories.php?cat_id= to search in categories so it would be "inurl:categories.php?cat_id=". This will search all the urls that has categories.php?cat_id= in them.
This is NOT indepth!