ABAP Select data from SAP table TWLV into internal table

Get Example source ABAP code based on a different SAP table
  Get ABAP code

Below is a number of ABAP code snippets to demonstrate how to select data from SAP TWLV table and store it within an internal table, including using the newer @DATA inline declaration methods. It also shows you various ways to process this data using ABAP work area, inline declaration or field symbols including executing all the relevant CONVERSION_EXIT routines specific to TWLV. See here for more generic Select statement tips.

Sometimes data within SAP is stored within the database table in a different format to what it is displayed to the user. These input/output conversation FM routines are what translates the data between the two formats.

There is also a full declaration of the TWLV table where each field has a char/string type for you to simply copy and paste. This allows you to use processing that is only available to these field types such as the CONCATENATE statement.

DATA: IT_TWLV TYPE STANDARD TABLE OF TWLV,
      WA_TWLV TYPE TWLV,
      GD_STR TYPE STRING.

DATA: lo_typedescr type REF TO cl_abap_typedescr.
DATA: lv_fieldname type fieldname.

FIELD-SYMBOLS: <FIELD> TYPE any.
FIELD-SYMBOLS: <TWLV> TYPE TWLV.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_TWLV.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM TWLV
  INTO TABLE IT_TWLV.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM TWLV
*  INTO TABLE @DATA(IT_TWLV2).
*--Further methods of using ABAP code to  select data from SAP database tables

*You can also declare the header/work area using the in-line DATA declaration method
READ TABLE IT_TWLV INDEX 1 INTO DATA(WA_TWLV2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_TWLV ASSIGNING <TWLV>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<TWLV>-MANDT = 1.
<TWLV>-LSTFL = 1.
<TWLV>-BEGRU = 1.
<TWLV>-STDVF = 1.
<TWLV>-AUTVF = 1.

ENDLOOP.

LOOP AT IT_TWLV INTO WA_TWLV.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_TWLV-AKTVF, sy-vline,
  WA_TWLV-AUFVF, sy-vline,
  WA_TWLV-VERF_MANU, sy-vline,
  WA_TWLV-ALLE_VAR, sy-vline,
  WA_TWLV-MEHRFACH, sy-vline,
  WA_TWLV-MSG_CODE, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_TWLV you want to display...

  WRITE:/ sy-uline.
* Aternatively use generic code to Write field values (and NAME) to screen report
  DO.
    ASSIGN COMPONENT sy-index OF STRUCTURE wa_TWLV TO <field>.
    IF sy-subrc <> 0. EXIT. ENDIF.
    WRITE:/ 'Field Value', <field>, sy-vline.
    gd_str = <field> .
    lo_typedescr ?= CL_ABAP_DATADESCR=>DESCRIBE_BY_DATA( <field> ).
    lv_fieldname = lo_typedescr->GET_RELATIVE_NAME( ).
    WRITE:/ 'Field Name', lv_fieldname.
  ENDDO.

  
*Redo loop but convert all fields from internal to out value  
LOOP AT IT_TWLV INTO WA_TWLV.


*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Convert all fields to display/output versions using conversion routines
  PERFORM convert_all_field_values CHANGING wa_EKKO.
	 
ENDLOOP.

  
*&---------------------------------------------------------------------*
*& Form convert_all_field_values
*&---------------------------------------------------------------------*
FORM convert_all_field_values CHANGING p_EKKO LIKE wa_EKKO.
DATA: ld_input(1000) TYPE c, ld_output(1000) TYPE C.
ENDFORM. 

*&---------------------------------------------------------------------*
*& Form process_as_string_field_values
*&---------------------------------------------------------------------*
FORM process_as_string_field_values CHANGING p_EKKO LIKE wa_EKKO.

TYPES: BEGIN OF T_TWLV_STR, 
MANDT TYPE STRING,
LSTFL TYPE STRING,
BEGRU TYPE STRING,
STDVF TYPE STRING,
AUTVF TYPE STRING,
AKTVF TYPE STRING,
AUFVF TYPE STRING,
VERF_MANU TYPE STRING,
ALLE_VAR TYPE STRING,
MEHRFACH TYPE STRING,
MSG_CODE TYPE STRING,
LIST_ALL TYPE STRING,
CHECK_ALL TYPE STRING,
FOLGE1 TYPE STRING,
VERKN1 TYPE STRING,
FOLGE2 TYPE STRING,
VERKN2 TYPE STRING,
FOLGE3 TYPE STRING,
VERKN3 TYPE STRING,
FOLGE4 TYPE STRING,
MAN_EXIT TYPE STRING,
PROF_ALG TYPE STRING,
PROF_WAGR TYPE STRING,
PROF_MAT TYPE STRING,
PROF_EXIT TYPE STRING,
MPZ_EXIT TYPE STRING,
LAY_EXIT TYPE STRING,
LAY_CHECK TYPE STRING,
VKP_CHECK TYPE STRING,
VKP_ZERO TYPE STRING,
OHNE_BAUST TYPE STRING,
LV_WRF1 TYPE STRING,
LV_NLIF TYPE STRING,
LAYVF TYPE STRING,END OF T_EKKO_STR.
DATA: WA_TWLV_STR type T_EKKO_STR.

DATA: ld_text TYPE string.

LOOP AT IT_EKKO INTO WA_EKKO.
  MOVE-CORRESPONDING wa_EKKO TO WA_EKKO_STR.
  CONCATENATE: sy-vline
WA_TWLV_STR-MANDT sy-vline 
WA_TWLV_STR-LSTFL sy-vline 
WA_TWLV_STR-BEGRU sy-vline 
WA_TWLV_STR-STDVF sy-vline 
WA_TWLV_STR-AUTVF sy-vline 
WA_TWLV_STR-AKTVF sy-vline 
WA_TWLV_STR-AUFVF sy-vline 
WA_TWLV_STR-VERF_MANU sy-vline 
WA_TWLV_STR-ALLE_VAR sy-vline 
WA_TWLV_STR-MEHRFACH sy-vline 
WA_TWLV_STR-MSG_CODE sy-vline 
WA_TWLV_STR-LIST_ALL sy-vline 
WA_TWLV_STR-CHECK_ALL sy-vline 
WA_TWLV_STR-FOLGE1 sy-vline 
WA_TWLV_STR-VERKN1 sy-vline 
WA_TWLV_STR-FOLGE2 sy-vline 
WA_TWLV_STR-VERKN2 sy-vline 
WA_TWLV_STR-FOLGE3 sy-vline 
WA_TWLV_STR-VERKN3 sy-vline 
WA_TWLV_STR-FOLGE4 sy-vline 
WA_TWLV_STR-MAN_EXIT sy-vline 
WA_TWLV_STR-PROF_ALG sy-vline 
WA_TWLV_STR-PROF_WAGR sy-vline 
WA_TWLV_STR-PROF_MAT sy-vline 
WA_TWLV_STR-PROF_EXIT sy-vline 
WA_TWLV_STR-MPZ_EXIT sy-vline 
WA_TWLV_STR-LAY_EXIT sy-vline 
WA_TWLV_STR-LAY_CHECK sy-vline 
WA_TWLV_STR-VKP_CHECK sy-vline 
WA_TWLV_STR-VKP_ZERO sy-vline 
WA_TWLV_STR-OHNE_BAUST sy-vline 
WA_TWLV_STR-LV_WRF1 sy-vline 
WA_TWLV_STR-LV_NLIF sy-vline 
WA_TWLV_STR-LAYVF sy-vline      INTO ld_text SEPARATED BY SPACE.

*Add any further fields from structure WA_EKKO_STR you want to CONCATENATE...
ENDLOOP.
ENDFORM.