create or replace function XX_TEST return varchar2 is
v_dtno  varchar2(10000);
begin
V_DTNO := NULL;
    for rec1 in (select 
   rct.ATTRIBUTE2||rct.ATTRIBUTE10||rct.ATTRIBUTE11  DTNO
   FROM     ra_customer_trx_all rtl,
    oe_order_headers mm,
             ar_customers ac,
             ra_customer_trx_lines_all rct,
             ra_cust_trx_line_gl_dist_all rgd
WHERE   ac.customer_id = rtl.bill_to_customer_id
AND     to_char(mm.order_number(+))= rtl.interface_header_attribute1
AND     rct.customer_trx_id = rtl.customer_trx_id
AND     rct.customer_trx_line_id = rgd.customer_trx_line_id
AND     rgd.customer_trx_id=41678
and     rct.inventory_item_id =413
group by rct.INVENTORY_ITEM_ID , rct.ATTRIBUTE2||rct.ATTRIBUTE10||rct.ATTRIBUTE11  
 ) 
    Loop
            V_DTNO := V_DTNO ||'-'||REC1.DTNO;
    End loop;
    
    dbms_output.put_line(' dt no is '||v_dtno);

return v_dtno;
end;