Performance on Select Single&Write AND Select*(For All Entries)&Read&Write

Question

Hi Experts,
I got a code review problem & we are in a argument.
I need the best performance code out of this two codes. I have tested this both on 5 & 1000 & 3000 & 100,000 & 180,000 records.
But still, I just need a second opinion of experts.
TYPES : BEGIN OF ty_account,
        saknr   TYPE   skat-saknr,
        END OF ty_account.
DATA : g_txt50      TYPE skat-txt50.
DATA : g_it_skat    TYPE TABLE OF skat,       g_wa_skat    LIKE LINE OF g_it_skat.
DATA : g_it_account TYPE TABLE OF ty_account, g_wa_account LIKE LINE OF g_it_account.
Code 1.
SELECT saknr INTO TABLE g_it_account FROM skat.
LOOP AT g_it_account INTO g_wa_account.
  SELECT SINGLE txt50 INTO g_txt50 FROM skat
    WHERE spras = 'E'
      AND ktopl = 'XXXX'
      AND saknr = g_wa_account-saknr.
  WRITE :/ g_wa_account-saknr, g_txt50.
  CLEAR : g_wa_account, g_txt50.
ENDLOOP.
Code 2.
SELECT saknr INTO TABLE g_it_account FROM skat.
SELECT * INTO TABLE g_it_skat FROM skat
  FOR ALL ENTRIES IN g_it_account
      WHERE spras = 'E'
        AND ktopl = 'XXXX'
        AND saknr = g_it_account-saknr.
LOOP AT g_it_account INTO g_wa_account.
  READ TABLE g_it_skat INTO g_wa_skat WITH KEY saknr = g_wa_account-saknr.
  WRITE :/ g_wa_account-saknr, g_wa_skat-txt50.
  CLEAR : g_wa_account, g_wa_skat.
ENDLOOP.
Thanks & Regards,
Dileep .C

Answer 1

Hi Dilip.
from you both the code I have found that you are selecting 2 diffrent fields.
In Code 1.
you are selecting SAKNR and then for these SAKNR you are selecting TXT50 from the same table.
and in Code 2 you are selecting all the fields from SAKT table for all the values of SAKNR.
I don't know whats your requirement.
Better you declare a select option on screen and then fetch required fields from SAKT table for the values entered on screen for SAKNR.
you only need TXT50 and SAKNR fields.
so declare two types one for SAKNR and another for TXT50.
Points to be remember.
1. while using for all entries always check the for all entries table should not be blank.
2. you will have to fetch all the key fields in table while applying for all entries,
    you can compare key fields with a constant which is greater than initial value.
3. while reading the table sort the table by the field on which you are going to read it.
try this:
TYPES : BEGIN OF ty_account,
saknr TYPE skat-saknr,
END OF ty_account.
TYPES : begin of T_txt50,
      saknr type saknr,
      txt50 type txt50,
end of t_txt50.
DATA: i_account type table of t_account,
      w_account type t_account,
      i_txt50 type table t_txt50,
      w_txt50 type t_txt50.
select SAKNR from SKAT into table i_account.
if sy-subrc = 0.
sort i_account by saknr.
select saknr txt50 from SKAT into table i_txt50
for all entries in i_account
where SAKNR = i_account-SAKNR
here mention al the primary keys and compare them with their constants.
endif.     
Note; here you need to take care that, you will have to fetch all the key fields in table i_txt50.
and compare those fields with there constants which should be greater than initial values.
they should be in proper sequence.
now for writing.
loop at i_account into w_account.
clear w_txt50.
sort i_txt50 by saknr.
read table i_txt50 into w_txt50 with key SAKNR = w_account-saknr
if sy-subrc = 0.
write: w_txt50-saknr, w-txt50-txt50.
clear w_txt50, w_account.
endif.
endloop.
Hope it wil clear your doubts.
Thanks
Lalit