Query Result Doesn't Display

Question

Hi All,
When i run the code below the query with SELECT statement display result as expected but other queries with LOOP and Object oriented running againt same table as that used in SELECT statement doesn't show anything, not even the output page. The status bar only showed the the program has complied without syntax error but no output page.
Please I need somebody to tell me why is the output not showing.
REPORT  read_table_flights.
DATA: itab_flight TYPE STANDARD TABLE OF sflight,
      wa_flight TYPE sflight,
      alv TYPE REF TO cl_salv_table.
FIELD-SYMBOLS: <wa_comp> TYPE any.
SELECT *
  FROM sflight INTO TABLE itab_flight
  WHERE carrid = 'LH' AND seatsmax < 250 .
Alternative one: Loop at table and write the different components of work area
LOOP AT itab_flight INTO wa_flight.
WRITE:  wa_flight-carrid,
        wa_flight-connid,
        wa_flight-fldate,
        wa_flight-price,
        wa_flight-currency,
        wa_flight-planetype,
        wa_flight-seatsmax,
        wa_flight-seatsocc,
        wa_flight-paymentsum.
        skip.
endloop.
**Alternative two: Loop at table with dynamic assign of component
*LOOP AT itab_flight INTO wa_flight.
DO.
   ASSIGN COMPONENT sy-index OF STRUCTURE wa_flight TO <wa_comp>.
   IF sy-subrc <> 0.
     SKIP.
     EXIT.
   ENDIF.
   WRITE <wa_comp>.
ENDDO.
*ENDLOOP.
object oriented way
*cl_salv_table=>factory( IMPORTING r_salv_table = alv
                       CHANGING  t_table      = itab_flight ).
*alv->display( ).

Answer 1

Thanks SaiRam  for your prompt reply. and thanks to everyone who has read my post.
The GUI i have is fresh installation. The SELECT query is working fine but LOOP doesn't display result even when SELECT does.
Please help me.