All about online game, (dedicated host), SQL, any tutorial? how to do it??

First of all, I mainly use javascript in unity3d. I searched so many places but still find nothing.

Here is my questions of how to make a online game:

1. Dedicated host, is there any tutorial for it?? It just like CS GO, League of Legends, etc. The problems I have is how to archieve it? Do I do both server and client side in 1 project and then run it and host it in the servers to do the server side logic? If not, how to do it? The reason that I dont use unity masterserver and let one of the player be the host is if that host disconnected, the whole game be destroyed or is there any other solution for example change the host and continue the game??

2. SQL, Is there any tutorials of how to do the database query, php, and connect to unity3d? Javascript will be the best but it is fine with C#

3. Servers, I heard photon, smartfox, etc. What is it? Is it something like masterserver or can I create databases on those servers, I have no idea how to create an online game, I just need the logic and basics.

4. Is there any cheap or free database I can use?

There are very limited resources I can find, so few videos, no explaination, it will be great if there are some detail resources or even videos to explain the logic and also how to archieve.