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  • ABAP 多层LOOP嵌套优化

    简易代码如下:

    量越大,时间差距越明显!!!!!!!

    DATA:lv_time_s TYPE timestampl,
         lv_time_e TYPE timestampl,
         lv_text   TYPE timestampl.
    DATA:lv_tabix  TYPE i.
    
    SELECT * FROM mara INTO TABLE @DATA(it_mara) UP TO 20000 ROWS.              "量越大 时间差越明显
    
    CHECK it_mara IS NOT INITIAL.
    
    SELECT * FROM marc INTO TABLE @DATA(it_marc) FOR ALL ENTRIES IN @it_mara WHERE matnr = @it_mara-matnr.
    
    GET TIME STAMP FIELD lv_time_s.
    
    DATA ls_data LIKE marc.
    DATA lt_data LIKE TABLE OF marc.
    LOOP AT it_mara INTO DATA(is_mara).
      LOOP AT it_marc INTO DATA(is_marc) WHERE matnr = is_mara-matnr.
        MOVE-CORRESPONDING is_marc TO ls_data.
        APPEND ls_data TO lt_data.
        CLEAR ls_data.
      ENDLOOP.
    ENDLOOP.
    GET TIME STAMP FIELD lv_time_e.
    
    lv_text = lv_time_e - lv_time_s.
    
    DESCRIBE TABLE lt_data LINES DATA(lv_num_l).
    WRITE: /(14) '普通循环时间:', lv_text, '条目数量:', lv_num_l.
    
    CLEAR:lv_text, lv_time_e, lv_time_s,lt_data.
    
    GET TIME STAMP FIELD lv_time_s.
    
    SORT:it_mara BY matnr,
         it_marc BY matnr.
    LOOP AT it_mara INTO is_mara.
      READ TABLE it_marc TRANSPORTING NO FIELDS WITH KEY matnr = is_mara-matnr BINARY SEARCH.
      IF sy-subrc = 0.
        lv_tabix = sy-tabix.
    
        LOOP AT it_marc FROM lv_tabix INTO is_marc.
          IF is_mara-matnr <> is_marc-matnr.
            EXIT.
          ENDIF.
    
          MOVE-CORRESPONDING is_marc TO ls_data.
          APPEND ls_data TO lt_data.
          CLEAR ls_data.
        ENDLOOP.
    
      ENDIF.
    
    ENDLOOP.
    GET TIME STAMP FIELD lv_time_e.
    
    DESCRIBE TABLE lt_data LINES DATA(lv_num_2).
    lv_text = lv_time_e - lv_time_s.
    
    WRITE: /(14) '优化循环时间:', lv_text, '条目数量:', lv_num_2.

    结果:

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    day31
  • 原文地址:https://www.cnblogs.com/seven1314pp/p/15162886.html
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