In which tables values will be inserted if I insert values into a view that its result is made out of inner join of 3 tables? Ι have the following view:
CREATE OR REPLACE VIEW public.my_view as 
SELECT
  col1,
  col11
from
  table_a JOIN table_b on table_a.id=table_b.a_id
  join
   (
     select id,col56 from table_c where col56 &gt; 3
   ) as filtered_c on table_a.id=filtered_c.a_id;

table_a is:
id: SERIAL PK
col1: INTEGER

table_b is:
id: SERIAL PK
col11: INTEGER
a_id FK table_a

table_c is:
id: SERIAL PK
col56 INTEGER
a_id FK table_a

As I saw upon postgresql wiki I can insert values to views that correspond to the appropriate tables. But in my case if I insert:
INSERT INTO my_view VALUES (7,88);

In which table the values will be inserted? As far as I know views are read-only tables.
A view that contains a join is not automatically updatable, that is, you cannot simply insert into such a view. The manual says (emphasis mine):

A view is automatically updatable if it satisfies all of the following conditions:

The view must have exactly one entry in its FROM list, which must be a table or another updatable view.
The view definition must not contain WITH, DISTINCT, GROUP BY, HAVING, LIMIT, or OFFSET clauses at the top level.
The view definition must not contain set operations (UNION, INTERSECT or EXCEPT) at the top level.

The view's select list must not contain any aggregates, window functions or set-returning functions.

The only way to insert into a view that does not meet these requirements is to create an INSTEAD OF INSERT trigger on it, in which case what valuees go to what tables is determined by the logic implemented in that trigger.