Problem with calculation in report.

Question

please let me know about below code . What can be possible errors .Because I didn't get true calculations . My purpose is to get ztab-pvprs for every material.
CLEAR atab . REFRESH atab .
  SELECT smblnr sbudat z~matnr
         zwerks zbwart z~menge
    INTO (atab-mblnr, atab-budat, atab-matnr,
          atab-werks, atab-bwart, atab-menge)
   FROM mkpf AS s INNER JOIN mseg AS z
     ON smblnr EQ zmblnr
    AND smjahr EQ zmjahr
   WHERE s~budat IN lv_budat
     AND z~matnr = son_tab-matnr
     AND z~werks = son_tab-bwkey
     AND z~bwart IN ('101', '102')
     AND z~aufnr NE ' ' .
    IF atab-bwart = '102'.
      atab-menge = atab-menge * -1.
    ENDIF.
    APPEND atab.
    CLEAR atab .
  ENDSELECT.
  CLEAR malz_itab2 .
  REFRESH malz_itab2 .
  LOOP AT atab.
    malz_itab2-matnr = son_tab-matnr.
    malz_itab2-menge = atab-menge.
    malz_itab2-poper = atab-budat+4(2).
  uretim_miktari = uretim_miktari + atab-menge .
  append malz_itab2.
  clear malz_itab2 .
  ENDLOOP.
loop at malz_itab2 .
      SELECT SINGLE * FROM mbew WHERE matnr = malz_itab2-matnr.
      SELECT  SINGLE *  FROM ckmlcr  WHERE kalnr = son_tab-kalnr
                                             AND curtp = s_curtp
                                             AND bdatj = s_bdatj
                                            AND poper = malz_itab2-poper
      x =  x + ( ckmlcr-pvprs * malz_itab2-menge ).
  if malz_itab2-menge > 0 .
        ztab-pvprs = x /  uretim_miktari.
      else .
       ztab-pvprs = 0 .
      ENDIF.
endloop.

Answer 1

Yusuf - Apologise for digressing but i looked at the select and it is not the best one. Couple of things:
1. Should use "Into table" in the select and avoid select-endselect
2. Loop and then select single shud be replaced by selecting mbew separately by "for all entries..." and then doind "read table...binary"
Else you will have lot of performance issues in Production server.
Regards,
Shireesh