Issue In internal table data population in the o/p

Question

Dear Guru , I have encountered an issue for which i am not able to findout the logic  . I have an internal table through which i am populating the below data for detail report format :->
Plant     Material Number          Storage Loc     Movement Type          Avg Days
019     0820B0073          MOD3          101               space
019     0820B0073          MOD3          101               space
019     0820B0073          MOD3          101               space
019     0820B0073          MOD3          101               space
019     0820B0073          MOD3          101               space
020     0820B0074          MOD4          101               space
020     0820B0074          MOD4          101               2
020     0820B0074          MOD4          101               3
The requirment is like this the summary report should show o/p like below addition of all the rows with respect to plant , material, storage location and movement type :-
Plant     Material Number          Storage Loc     Movement Type          Avg Days
019     0820B0073          MOD3          101               space
020     0820B0074          MOD4          101               5
but when i am adding it with respect to plant, material, storage location and movement type the o/p i am getting is like below
Plant     Material Number          Storage Loc     Movement Type          Avg Days
019     0820B0073          MOD3          101               0
020     0820B0074          MOD4          101               5
becasue addition of 5 spaces ( Avg Days )of plant 019 is coming as ZERO --> 0
so Guru what logic i should use to get the proper o/p,..I have Used Following logic to perform summation with respect to plant, material , storage loc and movement type.
CLEAR: wa_mkpf_mseg, w_werks, w_matnr, w_lgort, w_bwart.
LOOP AT t_mkpf_mseg INTO wa_mkpf_mseg.   
IF wa_mkpf_mseg-werks EQ w_werks AND wa_mkpf_mseg-matnr EQ w_matnr AND wa_mkpf_mseg-lgort EQ w_lgort AND wa_mkpf_mseg-bwart EQ w_bwart.
      CLEAR: wa_p_coi.
      READ TABLE t_p_coi INTO wa_p_coi WITH KEY werks = wa_mkpf_mseg-werks matnr = wa_mkpf_mseg-matnr lgort = wa_mkpf_mseg-lgort bwart = wa_mkpf_mseg-bwart.
     IF sy-subrc = 0.
     wa_p_coi-Avg Days    = wa_p_coi-Avg Days   + wa_mkpf_mseg-Avg Days.
     MODIFY t_p_coi FROM wa_p_coi TRANSPORTING Avg Days   .
     CLEAR: wa_p_coi, wa_p_coi.
     endif.
ELSE.
      wa_p_coi-werks                     = wa_mkpf_mseg-werks.
      wa_p_coi-matnr                     = wa_mkpf_mseg-matnr.
      wa_p_coi-bwart                   = wa_mkpf_mseg-bwart.
      wa_p_coi-lgort                     = wa_mkpf_mseg-lgort.
      wa_p_coi-Avg Days                  = wa_mkpf_mseg-Avg Days   .
     APPEND wa_p_coi TO t_p_coi.
           CLEAR: wa_p_coi.
ENDIF.
    w_werks = wa_mkpf_mseg-werks.
    w_matnr = wa_mkpf_mseg-matnr.
    w_lgort = wa_mkpf_mseg-lgort.
    w_bwart = wa_mkpf_mseg-bwart.
   CLEAR: wa_mkpf_mseg.
  ENDLOOP.

Answer 1

The soln what i found after working out
CLEAR: wa_mkpf_mseg, w_werks, w_matnr, w_lgort, w_bwart.
LOOP AT t_mkpf_mseg INTO wa_mkpf_mseg.
IF wa_mkpf_mseg-werks EQ w_werks AND wa_mkpf_mseg-matnr EQ w_matnr AND wa_mkpf_mseg-lgort EQ w_lgort AND wa_mkpf_mseg-bwart EQ w_bwart.
CLEAR: wa_p_coi.
READ TABLE t_p_coi INTO wa_p_coi WITH KEY werks = wa_mkpf_mseg-werks matnr = wa_mkpf_mseg-matnr lgort = wa_mkpf_mseg-lgort bwart = wa_mkpf_mseg-bwart.
IF sy-subrc = 0.
if wa_p_coi-Avg Days  = ' ' and wa_mkpf_mseg-Avg Days = ' '.
wa_p_coi-Avg Days = ' '.
ELSE
wa_p_coi-Avg Days = wa_p_coi-Avg Days + wa_mkpf_mseg-Avg Days.
Endif.
MODIFY t_p_coi FROM wa_p_coi TRANSPORTING Avg Days .
CLEAR: wa_p_coi, wa_p_coi.
endif.
ELSE.
wa_p_coi-werks = wa_mkpf_mseg-werks.
wa_p_coi-matnr = wa_mkpf_mseg-matnr.
wa_p_coi-bwart = wa_mkpf_mseg-bwart.
wa_p_coi-lgort = wa_mkpf_mseg-lgort.
wa_p_coi-Avg Days = wa_mkpf_mseg-Avg Days .
APPEND wa_p_coi TO t_p_coi.
CLEAR: wa_p_coi.
ENDIF.
w_werks = wa_mkpf_mseg-werks.
w_matnr = wa_mkpf_mseg-matnr.
w_lgort = wa_mkpf_mseg-lgort.
w_bwart = wa_mkpf_mseg-bwart.
CLEAR: wa_mkpf_mseg.
ENDLOOP.