动态内表在loop 和read table 中的应用

REPORT  yaotest.

*例子1
*TYPES:
*  BEGIN OF t_itab,
*    matnr LIKE mara-matnr,
*    maktx LIKE makt-maktx,
*  END OF t_itab,
*  BEGIN OF t_mara,
*    matnr LIKE mara-matnr,
*    meins LIKE mara-meins,
*  END OF t_mara.
*
*TYPES: t_tab_itab TYPE t_itab OCCURS 0,
*       t_tab_mara TYPE t_mara OCCURS 0.
*
*DATA: itab    TYPE t_tab_itab WITH HEADER LINE,
*      it_mara TYPE t_tab_mara.
*
*FIELD-SYMBOLS <fs> TYPE t_tab_itab.
**FIELD-SYMBOLS <fs> like itab.
*
*DATA: ls_itab TYPE t_itab.
*
*ASSIGN itab[] TO <fs>.
*
*LOOP AT <fs> INTO ls_itab.
*
*  READ TABLE <fs> INTO ls_itab INDEX 1.
*  EXIT.
*ENDLOOP.

*例子2

data:
  BEGIN OF t_itab,
    matnr LIKE mara-matnr,
    maktx LIKE makt-maktx,
  END OF t_itab.

data: t_tab_itab like t_itab OCCURS 0.

DATA: itab  like t_tab_itab WITH HEADER LINE.

FIELD-SYMBOLS <fs> like t_tab_itab.

DATA: ls_itab like t_itab.

ASSIGN t_tab_itab[] TO <fs>.

LOOP AT <fs> INTO ls_itab.

  READ TABLE <fs> INTO ls_itab with key matnr = ''.
  EXIT.
ENDLOOP.