ABAP Select data from SAP table M_WLFKA into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM M_WLFKA
*  INTO TABLE @DATA(IT_M_WLFKA2).
*--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_M_WLFKA INDEX 1 INTO DATA(WA_M_WLFKA2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<M_WLFKA>-MANDT = 1.
<M_WLFKA>-LFART = 1.
<M_WLFKA>-LIFRE = 1.
<M_WLFKA>-EKORG = 1.
<M_WLFKA>-EKGRP = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_M_WLFKA-WFDAT, sy-vline,
  WA_M_WLFKA-ERDAT, sy-vline,
  WA_M_WLFKA-ERNAM, sy-vline,
  WA_M_WLFKA-WBELN, sy-vline,
  WA_M_WLFKA-XBLNR, sy-vline,
  WA_M_WLFKA-BLDAT, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_M_WLFKA 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_M_WLFKA 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_M_WLFKA INTO WA_M_WLFKA.


*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 ALPHA, internal->external for field LIFRE
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_M_WLFKA-LIFRE
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_M_WLFKA-LIFRE.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field WBELN
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_M_WLFKA-WBELN
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_M_WLFKA-WBELN.
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_M_WLFKA_STR, 
MANDT TYPE STRING,
LFART TYPE STRING,
LIFRE TYPE STRING,
EKORG TYPE STRING,
EKGRP TYPE STRING,
WFDAT TYPE STRING,
ERDAT TYPE STRING,
ERNAM TYPE STRING,
WBELN TYPE STRING,
XBLNR TYPE STRING,
BLDAT TYPE STRING,
ZUONR TYPE STRING,END OF T_EKKO_STR.
DATA: WA_M_WLFKA_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_M_WLFKA_STR-MANDT sy-vline 
WA_M_WLFKA_STR-LFART sy-vline 
WA_M_WLFKA_STR-LIFRE sy-vline 
WA_M_WLFKA_STR-EKORG sy-vline 
WA_M_WLFKA_STR-EKGRP sy-vline 
WA_M_WLFKA_STR-WFDAT sy-vline 
WA_M_WLFKA_STR-ERDAT sy-vline 
WA_M_WLFKA_STR-ERNAM sy-vline 
WA_M_WLFKA_STR-WBELN sy-vline 
WA_M_WLFKA_STR-XBLNR sy-vline 
WA_M_WLFKA_STR-BLDAT sy-vline 
WA_M_WLFKA_STR-ZUONR sy-vline      INTO ld_text SEPARATED BY SPACE.

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