Hi VladiSlav,
As far as I know, there is no clear documentation supplied by PTC about the database schema. You may find some bits and pieces in different parts of Query Builder, JavaDocs, Windchill help and here in the Community (maps created by users).
Personally, I would recommend you to start with Query builder.
It will allow you to visually build the required objects and their relationships:

Define all the fields you want to get from those objects:

And then have a peek at the SQL query that builds the resulting table:

That should give you a good start.
Kind Regards,
Dmitry.