Table function in oracle I want to create a function that will return a table as a result. Now, I have written quite a big SQL that works, but as I need to push dates trough that SQL to the beginning, I need a funtion that will do that. Now, as an example, to see if I can get it working, I've created this so far:

create or replace type test_row as object (date_id number,day date)


and

create or replace type test_table as table of test_row


and written this function:

create or replace FUNCTION test_function 
(
  p_year_start_in integer,  
     p_year_end_in integer
) RETURN test_table AS 

      v_ret test_table;
      p_start date;
      p_end date;

BEGIN
    select td.date_id, td.day
    bulk collect into v_ret
    from T_D_DATES td
    where date_id between p_year_start_in and p_year_end_in;

  RETURN v_ret;
END test_function;


but the compiler throws an error. Specifically is says: 

PL/SQL: SQL Statement ignored for the select td.date_id, td.day part and

PL/SQL: ORA-00947: not enough values on  from T_D_DATES td

but I am not completely sure how to fix it. I've tried to make a PIPELINED 
 function but got lost on how to insert all my values from my select into the table type.

Funtions aren't really my forte and especially ones that return a table as a result. So, how can I write a function that would work with the sample select?

P.S: I've looked online for solutions but it's either a super simple loop that writes some hardcoded values or something really complex and I can't decipher it.
That will not work like that. test_table is a table of test_row objects, not 2 columns, so you need to create test_row objects from the 2 columns, like below:

create or replace FUNCTION test_function 
(
  p_year_start_in integer,  
     p_year_end_in integer
) RETURN test_table AS 

      v_ret test_table;
      p_start date;
      p_end date;

BEGIN
    select test_row(td.date_id, td.day)
    bulk collect into v_ret
    from T_D_DATES td
    where date_id between p_year_start_in and p_year_end_in;

  RETURN v_ret;
END test_function;
/