(2) 函数呼叫：
       CALL  FUNCTION  <module>
               IMPORTING   F1=a1….
               EXPORTING   F1=a1….
               CHANGING   F1=a1…
               TABLES      F1=a1…
               EXCEPTIONS  F1=a1…     
 

    

        (2) Data创建：使用Work Area
             DATA <f> <type> OCCURS <n> [WITH HEADER LINE].

        (3) Data创建：不使用Work Area（直接宣告）
             语法：DATA: BEGIN OF <f> OCCURS <n>,
                                                  <component declaration>,
                                                  ..............
                                     END OF <f>.   

三、使用内表
        ----------------------------------------------------------------------------------------------------------
        1、增加
              (1) 增加行（可能有重复行）
                   语法：APPEND [<wa> TO|INITIAL LINE TO] <itab>.

              (2) 根据标准关键字附加行（没有重复行）
                   语法：COLLECT [<wa> INTO] <itab>.

              (3) 表外增加
                   语法：APPEND LINES OF <itab1> [FROM <n1>] [TO <n2>] TO <itab2>.

        2、插入
              (1) 在指定行前插入
                   语法：INSERT [<wa> INTO|INITIAL LINE INTO] <itab> [INDEX <idx>].

              (2) 外表插入
                   语法：INSERT LINES OF <itab1> [FROM <n1>] [TO <n2>]
                                        INTO <itab2> [INDEX <idx>].    

        3、修改
              语法：MODIFY <itab> [FROM <wa>] [INDEX <idx>].    

        4、删除
              (1) 在循环中删除行
                   语法：Loop At <Itab> (Into type)
                                       DELETE <itab>.
                               End Loop.

              (2) 用索引删除行
                    语法：DELETE <itab> INDEX <idx>.

        5、查询
              (1) 循环读取
                   语法：LOOP AT <itab> [INTO <wa>] [FROM <n1>] [TO <n2>] [WHERE <condition>].
                                          .....
                               ENDLOOP. 

              (2) 用索引读取单行
                   语法：READ TABLE <itab> [INTO <wa>] INDEX <idx>.

              (3) 读取有关键字的单行
                   语法：READ TABLE <itab> [INTO <wa>] WITH KEY <key> [BINARY SEARCH].

         6、排序 
               语法：SORT <itab> [<order>] [AS TEXT]
                                      [BY <F1> [<order>] [AS TEXT] ... <fn> [<order>] [AS TEXT]]. 

         7、汇总
               (1) 非数值汇总
                    语法：COLLECT [<wa> INTO] <itab>.

               (2) 数值汇总
                    语法：Loop At <Itab> (Into type)
                                       Sum.
                               End Loop.

        8、清除
              (1) REFRESH <itab>.
                   解释：初始化没有表头的内表，清除所有元素
            
              (2) CLEAR <itab>.
                   解释：初始化有表头的内表，清除所有元素

              (3) FREE <itab>.
                   解释：重置内表并直接释放其内存，须在REFRESH或CLEAR后使用


        

3、 循环：DO和WHILE
       ------------------------------------
       (1) 计次循环：
                    DO [<n>TIMES] [VARYING <f> FROM <F1> NEXT <F2>].
                          <statement block>
                    ENDDO.

       (2) 无限循环：
                   DO .
                         <Statement Block>
                   ENDDO. 

        (3) 条件循环：
                   WHILE <condition> [VARY <f> FROM <F1> NEXT <F2>].
                        <statement block>
                   ENDWHILE.

         *  终止循环：
             ------------------------------------
             ① 无条件终止循环：CONTINUE
             ② 有条件终止循环：CHECK
             ③ 完全终止循环：  EXIT

       (2) 时间数据：
                    DATA: HOURS  TYPE  I,
                                MINUTES  TYPE  I,
                                T2  TYPE  T  VALUE ‘200000’,
                                T1  TYPE  T  VALUE  ‘183000’.
                   HOURS = (T2 - T1) /  3600.  “计算有几小时
                   MINUTES = (T2 – T1) / 60.  “计算几分钟

3、运算符号：
      --------------------------------------------------------------------
      (1) 算术符：+ - * / div mod

      (2) 比较符：> >= < <= = <> ><
                           EQ NE GT LT GE LE
                           And Or Not