Reference of Functions and Language

Hi,

I understood the use of the select statement, but I need a confirmation, please...

1.
I can use the select statement with a not linked table too, from any table in the DB?
2.
The select statement run with data fields only, or with formula fields too?
3.
I have three tables; Table A, linked to Table B; Table B linked to Table C; I can use the select statement from the Table A to obtain the Table C data (the Tables A and C are not directed linked); is it correct?
4.
Can I receive a lot of example with a little DB, to understand better the "How to do", please?

Thanks for all
Best regards
Roberto