Where to learn more SQL?

Hello I was wondering if anyone knew of other websites like this one where I could learn more advanced SQL ?

Hi textpro87838.
There are some websites from where you can get every kind of information about Advanced SQL. like tutorialspoint.com, khanacademy.org and 1keydata.com.
I hope these will help you.
Kenneth.

Yeah thanks a lot, do you have for python or ruby as well ?