vaule：collect在非数值字段相同的情况下，起到了数值字段汇总作用。
非数值字段不同的情况下，效果和append相同执行插入内表操作，当非数值字段相同的时候，则相当于modify的效果，只不过是将数值字段进行汇总相加后更新。
语法：collect W_table into I_table .
代码如下：
TYPES:BEGIN OF TY_TEST, ID(3) TYPE C, MENGE TYPE I, END OF TY_TEST. DATA:I_TEST TYPE TABLE OF TY_TEST, W_TEST TYPE TY_TEST. DATA:I_TEST2 TYPE TABLE OF TY_TEST. W_TEST-ID = '001'. W_TEST-MENGE = 10. APPEND W_TEST TO I_TEST. W_TEST-ID = '001'. W_TEST-MENGE = 70. APPEND W_TEST TO I_TEST. W_TEST-ID = '002'. W_TEST-MENGE = 20. APPEND W_TEST TO I_TEST. W_TEST-ID = '002'. W_TEST-MENGE = 50. APPEND W_TEST TO I_TEST. W_TEST-ID = '002'. W_TEST-MENGE = 80. APPEND W_TEST TO I_TEST. W_TEST-ID = '003'. W_TEST-MENGE = 30. APPEND W_TEST TO I_TEST. W_TEST-ID = '003'. W_TEST-MENGE = 90. APPEND W_TEST TO I_TEST. LOOP AT I_TEST INTO W_TEST. COLLECT W_TEST INTO I_TEST2."关键一步。。。" CLEAR:W_TEST. ENDLOOP. WRITE:/ 'Collect前的内容：' . WRITE:/1(12) '编号' , '数量'. LOOP AT I_TEST INTO W_TEST. WRITE:/ W_TEST-ID, ' ',W_TEST-MENGE. CLEAR:W_TEST. ENDLOOP. WRITE:/ . WRITE:/ 'Collect后的结果：' . WRITE:/1(12) '编号' , '数量'. LOOP AT I_TEST2 INTO W_TEST. WRITE:/ W_TEST-ID , ' ',W_TEST-MENGE. CLEAR:W_TEST. ENDLOOP.