ABAP Select data from SAP table DWLK2 into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP DWLK2 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 DWLK2. 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 DWLK2 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_DWLK2 TYPE STANDARD TABLE OF DWLK2,
      WA_DWLK2 TYPE DWLK2,
      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: <DWLK2> TYPE DWLK2.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_DWLK2.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM DWLK2
  INTO TABLE IT_DWLK2.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM DWLK2
*  INTO TABLE @DATA(IT_DWLK22).
*--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_DWLK2 INDEX 1 INTO DATA(WA_DWLK22).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_DWLK2 ASSIGNING <DWLK2>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<DWLK2>-VKORG = 1.
<DWLK2>-VTWEG = 1.
<DWLK2>-WERKS = 1.
<DWLK2>-DATAE = 1.
<DWLK2>-AENAM = 1.

ENDLOOP.

LOOP AT IT_DWLK2 INTO WA_DWLK2.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_DWLK2-KWDHT, sy-vline,
  WA_DWLK2-PRERF, sy-vline,
  WA_DWLK2-VKDAB, sy-vline,
  WA_DWLK2-VKBIS, sy-vline,
  WA_DWLK2-MSTAV, sy-vline,
  WA_DWLK2-MSTDV, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_DWLK2 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_DWLK2 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_DWLK2 INTO WA_DWLK2.


*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_DWLK2_STR, 
VKORG TYPE STRING,
VTWEG TYPE STRING,
WERKS TYPE STRING,
DATAE TYPE STRING,
AENAM TYPE STRING,
KWDHT TYPE STRING,
PRERF TYPE STRING,
VKDAB TYPE STRING,
VKBIS TYPE STRING,
MSTAV TYPE STRING,
MSTDV TYPE STRING,
RBZUL TYPE STRING,
SCAGR TYPE STRING,END OF T_EKKO_STR.
DATA: WA_DWLK2_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_DWLK2_STR-VKORG sy-vline 
WA_DWLK2_STR-VTWEG sy-vline 
WA_DWLK2_STR-WERKS sy-vline 
WA_DWLK2_STR-DATAE sy-vline 
WA_DWLK2_STR-AENAM sy-vline 
WA_DWLK2_STR-KWDHT sy-vline 
WA_DWLK2_STR-PRERF sy-vline 
WA_DWLK2_STR-VKDAB sy-vline 
WA_DWLK2_STR-VKBIS sy-vline 
WA_DWLK2_STR-MSTAV sy-vline 
WA_DWLK2_STR-MSTDV sy-vline 
WA_DWLK2_STR-RBZUL sy-vline 
WA_DWLK2_STR-SCAGR sy-vline      INTO ld_text SEPARATED BY SPACE.

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