[chu1720]

Is there any website (other than this official wiki) that have a very detailed tutorial that can let learn scripting systematically

[thresh0ld]

The wiki is all you need to help get you started...also, try learning from the existing plug-ins.

[rhelgeby]

I think he mean a complete tutorial (like in books) where you're guided through easy and general stuff first and then advance with more complicated stuff. With small and bigger example plugins and such.

I'd actually like to write a such tutorial myself, but don't have time for everything I want to do. I wonder if it's even worth it, since SourcePawn won't last forever.

The Zombie:Reloaded plugin (link in my signature) that I and Greyscale is working on is also meant as a learning resource. Lots of comments in the code too. Since it does so much and use a lot of coding concepts it might be useful inspiration. Though you won't learn anything systematically by this.