ABAP Select data from SAP table WWGD into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP WWGD 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 WWGD. 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 WWGD 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_WWGD TYPE STANDARD TABLE OF WWGD,
      WA_WWGD TYPE WWGD,
      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: <WWGD> TYPE WWGD.

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM WWGD
*  INTO TABLE @DATA(IT_WWGD2).
*--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_WWGD INDEX 1 INTO DATA(WA_WWGD2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<WWGD>-MAKTX1 = 1.
<WWGD>-TAXKM = 1.
<WWGD>-VTEXT = 1.
<WWGD>-CLASS1 = 1.
<WWGD>-KLSCHL1 = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_WWGD-KLSCHL2, sy-vline,
  WA_WWGD-CLASS2, sy-vline,
  WA_WWGD-MAKTX2, sy-vline,
  WA_WWGD-VTXTK, sy-vline,
  WA_WWGD-MSEHI, sy-vline,
  WA_WWGD-MSEHT, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_WWGD 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_WWGD 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_WWGD INTO WA_WWGD.


*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.

*Conversion exit CUNIT, internal->external for field MSEHI
CALL FUNCTION 'CONVERSION_EXIT_CUNIT_OUTPUT'
  EXPORTING
    input =                      WA_WWGD-MSEHI
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_WWGD-MSEHI.
WRITE:/ 'New Value:', ld_input.

*Conversion exit CUNIT, internal->external for field MSEHI_V
CALL FUNCTION 'CONVERSION_EXIT_CUNIT_OUTPUT'
  EXPORTING
    input =                      WA_WWGD-MSEHI_V
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_WWGD-MSEHI_V.
WRITE:/ 'New Value:', ld_input.
ENDFORM. 

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

TYPES: BEGIN OF T_WWGD_STR, 
MAKTX1 TYPE STRING,
TAXKM TYPE STRING,
VTEXT TYPE STRING,
CLASS1 TYPE STRING,
KLSCHL1 TYPE STRING,
KLSCHL2 TYPE STRING,
CLASS2 TYPE STRING,
MAKTX2 TYPE STRING,
VTXTK TYPE STRING,
MSEHI TYPE STRING,
MSEHT TYPE STRING,
MSEHI_V TYPE STRING,
MSEHT_V TYPE STRING,
TAKLV TYPE STRING,
TAKLV_V TYPE STRING,
MTART TYPE STRING,END OF T_EKKO_STR.
DATA: WA_WWGD_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_WWGD_STR-MAKTX1 sy-vline 
WA_WWGD_STR-TAXKM sy-vline 
WA_WWGD_STR-VTEXT sy-vline 
WA_WWGD_STR-CLASS1 sy-vline 
WA_WWGD_STR-KLSCHL1 sy-vline 
WA_WWGD_STR-KLSCHL2 sy-vline 
WA_WWGD_STR-CLASS2 sy-vline 
WA_WWGD_STR-MAKTX2 sy-vline 
WA_WWGD_STR-VTXTK sy-vline 
WA_WWGD_STR-MSEHI sy-vline 
WA_WWGD_STR-MSEHT sy-vline 
WA_WWGD_STR-MSEHI_V sy-vline 
WA_WWGD_STR-MSEHT_V sy-vline 
WA_WWGD_STR-TAKLV sy-vline 
WA_WWGD_STR-TAKLV_V sy-vline 
WA_WWGD_STR-MTART sy-vline      INTO ld_text SEPARATED BY SPACE.

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