This tutorial will teach you use sqlmap in kali, You can find tutorials like this in Internet mine little more detail and, some member wanted it so, I'm doing

First, Search google dork list find dork you want dosen't matter in this tutorial

Now i assume you picked the dork you want
Go website look for sql syntax error add url this ' " marks

Now it says sql syntax error do you know why this is happens ?
its happen because when you write this to url, Php tries to run code that already writen but adds extra this from url but when you add this ' or " code looks like this; (very basic example) echo "tutorial"; " <<<< its add extra Quotation Marks it fucks up the code (basically)

sqlmap -u (means url) www.victim.com?vurnablepart=35 --dbs (means database)

Done.