Yes, you can follow the same track.

CREATE table categoria(

[id_categoria] [int] NOT NULL,

[categoria] [nvarchar](50) NULL

);

INSERT INTO categoria

VALUES

(1, 'horror'),

(2, 'fantascienza');

CREATE table film(

[id_film] [int] NOT NULL,

[film] [nvarchar](50) NULL,

[fk_categoria] [int] NULL

);

INSERT INTO film

VALUES

(1,'titolo 1', 1),

(2,'titolo 2', 1),

(3,'titolo 3', 2);

CREATE TABLE [dbo].[sub_film](

[id_sub_film] [int] NOT NULL,

[sub_titolo] [varchar](50) NULL,

[fk_film] [int] NULL

);

INSERT INTO sub_film

VALUES

(1,'sub_titolo 2.0', 2),

(2,'sub_titolo 2.1', 2),

(2,'sub_titolo 3.0', 3)

;

select title from

(

select f.[fk_categoria], f.[id_film], [id_sub_film], title= replicate(' ',6)+[sub_titolo]

from sub_film as sf

join film as f on sf.[fk_film] = f.[id_film]

union all

select [fk_categoria], [id_film], null, title= replicate(' ',3)+[film]

from film

union all

select

[id_categoria], null, null, title = [categoria]

from categoria

) as t

order by [fk_categoria], [id_film], [id_sub_film]

A word of caution. You haven't declared any foreign key. And referencing columns are nullable. You should either correct it or decide on where should 'orphan' films and subfilms go and rewrite the query accordingly.