[SAP ABAP] Group By로 중복 체크하기

Group By를 이용하여 중복 항목을 검사하는 방법을 배워보자

          LOOP AT gt_01 INTO DATA(ls_dpcheck)
              GROUP BY ( matnr = ls_dpcheck-matnr
                         werks = ls_dpcheck-matnr
                         size = GROUP SIZE )
              ASCENDING REFERENCE INTO DATA(group_ref).

            CHECK group_ref->*-size > 1.
            MESSAGE TEXT-e04 TYPE 'S' DISPLAY LIKE 'E'.
            RETURN.
          ENDLOOP.