FILTER是ABAP中的一个关键字，用于在内部表中进行数据筛选和过滤，以便于提取所需的数据集。

FILTER关键字用于从内部表中筛选符合特定条件的数据行。它通过提供条件表达式，只返回满足条件的数据行，从而在不修改原始数据的情况下生成一个新的内部表。FILTER关键字在处理大量数据时非常有用，可以有效地减少内部表的大小，同时提高代码的可读性和可维护性。

REPORT ZJERRY_FILTER.

DATA: lt_spfli TYPE STANDARD TABLE OF spfli
       WITH NON-UNIQUE SORTED KEY carr_city COMPONENTS carrid,
      lt_lh TYPE TABLE OF spfli.

SELECT * INTO TABLE lt_spfli FROM spfli.

"data(lt) = FILTER #( lt_spfli using key carrid where carrid = '1' ).

lt_lh = FILTER #( lt_spfli using key carr_city where carrid = conv #( 'LH' ) ).
BREAK-POINT.

filter 之前：

filter 之后：

第二个例子：

report z.

TYPES: BEGIN OF ty_person,
           name type string,
           age type int4,
      end of ty_person.

data: lt_person type STANDARD TABLE OF ty_person
                        with NON-UNIQUE SORTED KEY person_key COMPONENTS age,
      lt_old1 like lt_person,
      lt_old2 like lt_person,
      ls_person type ty_person.

ls_person-name = 'Tom'. ls_person-age = '21'. INSERT ls_person into table lt_person.
ls_person-name = 'Jim'. ls_person-age = '62'. INSERT ls_person into table lt_person.
ls_person-name = 'Bob'. ls_person-age = '70'. INSERT ls_person into table lt_person.
ls_person-name = 'Kate'. ls_person-age = '30'. INSERT ls_person into table lt_person.

LOOP AT lt_person INTO ls_person WHERE age > 60.
   INSERT ls_person INTO TABLE lt_old1.
ENDLOOP.

lt_old2 = FILTER #( lt_person USING KEY person_key where age > 60 ).

IF lt_old1 = lt_old2.
   BREAK-POINT.
ENDIF.