Update a select-option From Table

Question

Hi,
I'm originally a C++ developer trying to learn ABAP.
I want to append values to a select-option from a table if another select-option is specified.  I wrote some code that I believe will work but looks very inefficient to me.  Any advice on how to streamline this process would appreciated.
The following is pseudo code and I left out some tweaks for simplicity and understanding but the basic idea is there.  I want to add selection criteria to a select-option based upon a second select option (that may or may not be provided) table lookup.
Example:
DATA: groups TYPE table3.
SELECT-OPTIONS:
     s_accountNo FOR table1-accountNo,
     s_accountGroupNo FOR table2-accountGroupNo.
**** get the Account Groups that meet the selection criteria.
START-OF-SELECTION
     SELECT * INTO TABLE groups
          FROM table3
          WHERE accountGroupNo IN s_accountGroupNo.
**** Remove duplicate accounts from the Account Groups
SORT groups BY accountNo.
DELETE ADJACENT DUPLICATES FROM groups COMPARING accountNo.
**** Append the account #'s onto the s_accountNo range/select-option
LOOP AT groups.
     APPEND groups-accountNo TO s_accountNo.
ENDLOOP.
**** manually edit the  s_accountNo to have the correct option/sign for use in further select statements.
LOOP AT s_accountNo.
     s_accountNo-sign = 'I'.
     s_accountNo-option = 'EQ'.
     MODIFY s_accountNo.
ENDLOOP.
Thanks much,
-Chris

Answer 1

The actual selection is fairly complicated from my point of view.  I wrote the accountNo example to make things less confusing for me as much as anyone else, not to hide anything.  I also didn't expect this amount of feedback, though it is appreciated.
The eventual select statement that is done is the following:
  SELECT DISTINCT vttp~zseq_num
                  likp~vbeln
                  likp~lprio
                  likp~vstel
                  lips~werks
                  likp~lgnum
                  lips~posnr
                  lips~lgort
                  lips~vgbel
                  lips~vgpos
                  lips~sobkz
                  lips~lfimg
                  lips~vrkme
                  lips~matnr
                  lips~volum
                  mara~raube
                  vttk~dplbg
                  vttp~tknum
                  vttp~tpnum
                  likp~berot
                  likp~vkorg
                  likp~lfart
                  INTO TABLE temp_deliveries
  FROM vttk
       INNER JOIN vttp
       ON vttk~tknum = vttp~tknum
       INNER JOIN likpuk AS likp
       ON vttp~vbeln = likp~vbeln
       INNER JOIN lipsup AS lips
       ON likp~vbeln = lips~vbeln
       INNER JOIN mara
       ON lips~matnr = mara~matnr
  WHERE likp~vstel = p_vstel
    AND lips~werks = p_werks
    AND likp~lgnum IN s_lgnum
    AND likp~vbeln IN s_vbeln
    AND lips~vgbel IN s_vgbel
    AND vttk~dplbg IN s_dplbg
    AND vttk~tknum IN s_tknum
    AND mara~raube = p_raube
    AND likp~lfart IN ('ZLF', 'NL')
    AND lips~kosta <> 'C'
    AND lips~kosta <> ''
    AND likp~kostk <> 'C'
    AND likp~vbtyp = outbound.
and the structure it is put into is the following:
TYPES: BEGIN OF type_deliveries,
          zseq_num    TYPE vttp-zseq_num,
          vbeln       TYPE likp-vbeln,
          lprio       TYPE likp-lprio,
          vstel       TYPE likp-vstel,
          werks       TYPE likp-werks,
          lgnum       TYPE likp-lgnum,
          posnr       TYPE lips-posnr,
          lgort       TYPE lips-lgort,
          vgbel       TYPE lips-vgbel,
          vgpos       TYPE lips-vgpos,
          sobkz       TYPE lips-sobkz,
          lfimg       TYPE lips-lfimg,
          vrkme       TYPE lips-vrkme,
          matnr       TYPE lips-matnr,
          volum       TYPE lips-volum,
          raube       TYPE mara-raube,
          dplbg       TYPE vttk-dplbg,
          tknum       TYPE vttk-tknum,
          tpnum       TYPE vttp-tpnum,
          berot       TYPE likp-berot,
          vkorg       TYPE likp-vkorg,
          lfart       TYPE likp-lfart,
          sdabw       type likp-sdabw,
          orig_lgort  TYPE lips-zzorig_lgort,
          selected    TYPE flag,
          counter(15) TYPE n,
        END OF type_deliveries.
Currently there is a select option for tknum and I am attempting (successfully with my change shown above, though as many have pointed out I may be misusing the intended functionality) to add another select-option for s_pickno which is a field of a custom table that has pickno as one of it's unique keys and tknum as another of it's fields.  The idea is to be able to take a pickno and use it to find all the tknum's associated and then use them in the select statement above as well as any tknum's provided as initial input by the user.  If there is a better method than modifying the s_tknum selection I'm open to feedback.
Apologies that my initial example did not portray this, but being new I was a little overwhelmed myself and want something I can wrap my head around better.  There's my wall of text