Logic SELECT CASE WHEN

I would like help in building the following logic:

I have my main table and two other tables A and B, which have foreign key of main.

When a column X is filled in the table I need to classify my information as being of " Type 1" When there is any field in Table B being B. foreign ID = P. id_principal. I need to classify my information as being of "Type 2"

But, in field X of table a there are some filled only with comma',' in these cases, even when I have filled with comma and there is nothing in Table B then my information is still "Type 1"

And if it is filled only with comma', 'and there is record in Table B then it will be only of"Type 2"

And finally when column x of Table A is filled and there is record in Table B then it is information of "Type 1 and type 2"

Table main:

Table A

Table B

As you can see in this example the IDS 1 and 3 of the main table should be classified as Type 1

ID 6 should only be of type 2

And the other IDs being like Type 1 and two

With the following query

select

(
CASE WHEN (A.de_inf is not null or A.de_inf != '') and A.de_inf != ','
        AND EXISTS (select tit_inf from B where tit_inf IS NOT NULL OR tit_inf != '') 
            THEN 'Tipo 1 e Tipo 2' 

ELSE

    CASE WHEN A.de_inf = ',' or (A.de_inf is not null or A.de_inf != '')
                AND NOT EXISTS (select tit_inf from B where tit_inf IS NOT NULL OR tit_inf != ''
            )  
                THEN 'Tipo 1'

ELSE

    CASE WHEN  A.de_inf = ',' 
        AND EXISTS (select tit_inf from B where tit_inf IS NOT NULL OR tit_inf != '') 
        THEN 'Tipo 2'

                end 
                end
                end


) as tipo



from
principal as p

left join A on p.id_inf = A.id_inf

I got this result

Or also this shape:

SELECT
p.id_inf,
 (
CASE WHEN A.de_inf != ',' THEN
CASE WHEN A.de_inf is not null or A.de_inf != '' THEN 
CASE WHEN  EXISTS (select tit_inf from B where tit_inf IS NOT NULL OR tit_inf != '')  
THEN 'Tipo 1 e 2' ELSE 'Tipo 1'
END
end

else
'Tipo 2'
END
) AS tipo
from
principal as p

left join A on p.id_inf = A.id_inf