SELECT sum(honoraria_amount)
FROM table_1

table_id
----
1
39
42

SELECT sum(honoraria_amount)
FROM table_x

CREATE VIEW union_table (id, name)
  AS      ( SELECT honoraria_amount,... FROM foreign_table_1 UNION ALL
            SELECT honoraria_amount, ... FROM foreign_table_2
  ) ;

create or replace function sum_table(
    tid integer
) returns numeric as $$
declare
    _out numeric;
begin
    execute 'select sum(honoraria_amount) from table_' || tid::text || ';' into _out;
    return _out;
end;
$$ language plpgsql;

with
    __tables as(
        select unnest(array[1, 39, 42]) as table_id
    )
select
    table_id,
    sum_table(table_id)
from
    __tables