You originally said "everything you can do with it" rather than just the basics though. Those goal posts moved pretty far.
I agree with learning most of your examples in an afternoon, but really knowing SQL takes a hell of a lot longer than that. In fact even the most SQL shy ORM preferring devs I've worked with still know those basics.
Where do you work? That must be a great place! Most devs I know, even talented ones, have never done a recursive query, and a lot of them don't even know it's possible.
I agree with learning most of your examples in an afternoon, but really knowing SQL takes a hell of a lot longer than that. In fact even the most SQL shy ORM preferring devs I've worked with still know those basics.