1つのクエリで多対多のテーブルを選択

このクエリを試してください

SELECT book.BookName, autor.FirstName, autor.LastName, rubric.RubricName 
FROM bookautor
JOIN book ON book.BookID=bookautor.BookID 
JOIN autor on autor.AutorID=bookautor.AutorID 
left join bookrubric on book.BookID=bookrubric.BookID
LEFT JOIN rubric ON rubric.RubricID=bookrubric.RubricID;