An Internal Table example with SAP - ABAP..

..
REPORT TEST LINE-COUNT 8.
 
* Structure I created: ZTMP_TEST_CUST_STRU
* View name: Z_KNA1_VBRK
 
DATA companyCodes TYPE T001.
DATA pageHeader TYPE STRING.
 
DATA:  BEGIN OF BILL_DOCS_TAB OCCURS 5,
   VBELN TYPE Z_KNA1_VBRK-VBELN,
   FKDAT TYPE Z_KNA1_VBRK-FKDAT,
   KUNNR TYPE Z_KNA1_VBRK-KUNNR,
   NAME1 TYPE Z_KNA1_VBRK-NAME1,
   ORT01 TYPE Z_KNA1_VBRK-ORT01,
   NETWR TYPE Z_KNA1_VBRK-NETWR,
   KURRF TYPE Z_KNA1_VBRK-KURRF,
  END OF BILL_DOCS_TAB.
 
DATA TOTAL TYPE VBRK-NETWR.
 
TOP-OF-PAGE.
 WRITE pageHeader.
 
START-OF-SELECTION.
 SELECT SINGLE * FROM T001 INTO companyCodes WHERE BUKRS = 2000.
 
 CONCATENATE TEXT-001 companyCodes-BUTXT INTO pageHeader.
 
 SELECT VBELN FKDAT KUNNR NAME1 ORT01 NETWR KURRF FROM Z_KNA1_VBRK INTO
  TABLE BILL_DOCS_TAB WHERE BUKRS = 2000.
 
 LOOP AT BILL_DOCS_TAB INTO BILL_DOCS_TAB.
  WRITE:/5(5) SY-TABIX, BILL_DOCS_TAB-VBELN, BILL_DOCS_TAB-FKDAT, 
   BILL_DOCS_TAB-KUNNR, BILL_DOCS_TAB-NAME1, 
   BILL_DOCS_TAB-ORT01, (17) BILL_DOCS_TAB-NETWR.
  TOTAL = TOTAL + BILL_DOCS_TAB-NETWR.
 ENDLOOP.
 
 WRITE: / 'Total is:', TOTAL.
END-OF-SELECTION.

And the result is as follows: