How to avoid the loop inside the loop? as it reduces the performance.

Question

hi masters,
i have 2 internal tables having 1 same field. eg table itab having f1, f2, f3 fields and itab1 having f1, f4 and f5 fields. let us consider the data in the itab and itab1 is like below given
itab-f1   itab-f2   itab-f3                 itab1-f1     itab1-f4   itab1-f5
10        aa         11                      10             abc       456
10        bb         15                      10             def        655
10        ff           13                      10             ghi        456
11        dd         16                      10             tre         455
11        zz         24                      11             ftr          256
11        ii           54                      11             kjh         556
12        hh         24                      12             fjk          751
now i want the result in final table like below
f1         f2       f3         f4         f5
10        aa      11      abc      456
10        aa      11      def       655
10        aa      11      ghi       456
10        aa      11      tre       455
10        bb      15      abc      456
10        bb      15      def       655
10        bb      15      ghi       456
10        bb      15      tre       455
10        ff        13      abc      456
10        ff        13      def      655
10        ff        13      ghi      456
10        ff        13      tre       455
11        dd      16      ftr        256
11        dd      16      kjh      556
11        zz      24      ftr       256
11        zz      24      kjh      556
11        ii        54      ftr       256
11        ii        54      kjh      556
12        hh      24      fjk       751
i can get this result using the
Loop at itab.
loop at itab1 where f1 = itab-f1.
process....
endloop.
endloop.
but it is very slow. i want to avoid this loop inside the loop and i want to implement the same program using read table.. like below..
Loop at itab.
Read table itab1 with key ....
process...
endloop.
Is it possible? to get multiple records from itab2 using read statement or with READ statement that using CASE Statement or IF statemetnt.
Plz help me...

Answer 1

hi,
please try the following code
TYPES:
  begin of ty_itab2,
   f1
   f2
   f3
   f4
   f5
  end of ty_itab2.
DATA:
  lw_tab2tmp type ty_itab2,
  lt_tab2tmp type standard table of ty_itab2.
sort it_itab by f1.
loop at it_itab into lw_itab.
  at new f1.
    CLEAR lt_tab2tmp[].
    loop at it_itab1 into lw_itab1 where f1 = lw_itab-f1.
      CLEAR lw_tab2tmp.
      move-corresponding lw_itab1 to lw_tab2tmp.
      append lw_tab2tmp into lt_tab2tmp.
    end loop.
    "while there is no data with f1 in it_itab1
    if lt_tab2tmp is initial.
      lw_tab2tmp-f1 = lw_itab-f1.
      append lw_tab2tmp into lt_tab2tmp.
    endif.
  end at.
  CLEAR lw_tab2tmp.
  MOVE-CORRESPONDING lw_itab to lw_tab2tmp.
  modify lt_tab2tmp from lw_tab2tmp TRANSPORTING f2 f3 where not f1 is initial.
  append lines of lt_tab2tmp into lt_itab2.
end loop.
lt_itab2 is the final table.
There may be some syntactically errors.
I have not a system to test it now, please test it.