在sap我有一个表，有行具有相同的名称，但不同的数量。我想这样总结这些行:
SELECT c~aufnr
p~matnr p~bdter p~meins p~baugr p~dbskz p~erfmg p~aufnr
f~maktx
INTO CORRESPONDING FIELDS OF TABLE it_tab
FROM afpo AS c
INNER JOIN resb AS p ON c~aufnr = p~aufnr
INNER JOIN makt AS f ON p~matnr = f~matnr.
LOOP AT it_tab INTO fs_tab.
COLLECT fs_tab INTO it_tab_collected.
ENDLOOP.
it_tab = it_tab_collected.
但是在这种情况下，它只对完全相同的行求和。我只需要对同名的行求和。
我怎样才能做到这一点?
问候,亚历山大。
正如icbytes已经说过的，COLLECT使用关键字段来确定聚合哪些字段。我建议定义一些数据类型来匹配您的场景:
TYPES: BEGIN OF t_my_type,
key_a TYPE foo,
key_b TYPE foo,
nokey_c TYPE foo,
nokey_d TYPE foo,
END OF t_my_type,
tt_my_type_list TYPE STANDARD TABLE OF t_my_type WITH DEFAULT KEY,
tt_my_type_hash TYPE HASHED TABLE OF t_my_type WITH KEY key_a key_b.
DATA: lt_result TYPE tt_my_type_list,
lt_sums TYPE tt_my_type_hash.
FIELD-SYMBOLS: <ls_result> TYPE t_my_type.
LOOP AT lt_result ASSIGNING <ls_result>.
COLLECT <ls_result> INTO lt_sums.
ENDLOOP.
…或者您可能希望首先使用聚合函数…
我会把从COLLECT中去掉，即使你可以节省几行代码，也没有必要使用它，而且无缘无故地添加了约束
我在维护/添加功能到以前使用COLLECT编写的代码时遇到了问题，因为它不允许将非关键非数字字段添加到内部表中，有时我被迫修改很多COLLECT句子或向代码引入不必要的复杂性(如使用额外的内部表)。
示例(以vwegert的示例为基础，他很好地解释了如何正确使用COLLECT):
TYPES: BEGIN OF t_my_type,
key_a TYPE foo,
key_b TYPE foo,
""" with COLLECT all 'foo' types **has to be** numeric
nokey_c TYPE foo,
nokey_d TYPE foo,
""" if you ever need to add something like a note field to the table
""" you'll find out that you have to change all the COLLECT sentences
""" because this new field wouldn't let the code compile
nokey_notes(50) type c,
END OF t_my_type,
tt_my_type_list TYPE STANDARD TABLE OF t_my_type WITH DEFAULT KEY,
tt_my_type_hash TYPE HASHED TABLE OF t_my_type WITH KEY key_a key_b.
DATA: lt_result TYPE tt_my_type_list,
lt_sums TYPE tt_my_type_hash.
FIELD-SYMBOLS: <ls_result> TYPE t_my_type.
""" just imagine you need the 'nokey_notes' field for an ALV for user input.
PERFORM show_alv USING lt_result.
""" and you don't care about this new field when doing
""" the sum/average or whatever you are trying to calculate
""" well, it won't work with COLLECT...
LOOP AT lt_result ASSIGNING <ls_result>.
COLLECT <ls_result> INTO lt_sums.
ENDLOOP.
我的建议将使用AT... ENDAT(除了SELECT的聚合函数，这是一个很好的选择，特别是如果你不需要单独的数据)。
当然，代码会增加一些额外的行，但在我看来/经验中，它们是值得的，因为代码在将来会更容易维护。
TYPES: BEGIN OF t_my_type,
key_a TYPE foo,
key_b TYPE foo,
""" with COLLECT all 'foo' types **has to be** numeric
nokey_c TYPE foo,
nokey_d TYPE foo,
""" without COLLECT you are able to add new non-key non-numeric fields
nokey_notes(50) type c,
END OF t_my_type,
tt_my_type_list TYPE STANDARD TABLE OF t_my_type.
DATA: lt_result TYPE tt_my_type_list,
lt_sum TYPE tt_my_type_list.
lwa_sum TYPE t_my_type.
FIELD-SYMBOLS: <ls_result> TYPE t_my_type.
""" just imagine you need the 'nokey_notes' field for an ALV for user input.
PERFORM show_alv USING lt_result.
""" sorting is important when using AT... ENDAT, there are other gotchas too
""" make sure you read its documentation carefully if you never used it
""" (like everything right? :P)
SORT lt_result BY key_a key_b.
REFRESH lt_sum.
""" and you don't care about 'nokey_notes' field when doing calculation
LOOP AT lt_result ASSIGNING <ls_result>.
AT NEW key_b.
""" this get executed when the work area's primary keys
""" change, good time to prepare the lwa_sum work area.
CLEAR lwa_sum.
lwa_sum-key_a = lwa_sum-key_a.
lwa_sum-key_b = lwa_sum-key_b.
ENDAT.
""" do whatever math/logic is need with the fields
lwa_sum-nokey_c = lwa_sum-nokey_c + <ls_result>-nokey_c.
lwa_sum-nokey_d = lwa_sum-nokey_d + <ls_result>-nokey_d.
AT END OF key_b.
""" this get executed when the work area's primary keys
""" is about to change (in next iteration) or at the last
""" record of the table
""" good place to save the results to a new internal table
APPEND lwa_sum to lt_sums.
ENDAT.
ENDLOOP.
AFAIK collect使用键，因为它可以决定哪些行应该创建聚合。如果在数值前有其他字符值，请在另一个tab中删除它们，以便填充的唯一类似c的列将是"name"。这将作为abap处理器聚合的唯一键。