ABAP Select data from SAP table WCAK into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM WCAK
*  INTO TABLE @DATA(IT_WCAK2).
*--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_WCAK INDEX 1 INTO DATA(WA_WCAK2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<WCAK>-MANDT = 1.
<WCAK>-LUNR = 1.
<WCAK>-VERNR = 1.
<WCAK>-OBJNR = 1.
<WCAK>-STXT = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_WCAK-LFLG, sy-vline,
  WA_WCAK-REJCFLG, sy-vline,
  WA_WCAK-REFOBJ, sy-vline,
  WA_WCAK-CRNAME, sy-vline,
  WA_WCAK-CRDATE, sy-vline,
  WA_WCAK-CRTIME, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_WCAK 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_WCAK 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_WCAK INTO WA_WCAK.


*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 LUNR
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_WCAK-LUNR
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_WCAK-LUNR.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field VERNR
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_WCAK-VERNR
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_WCAK-VERNR.
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_WCAK_STR, 
MANDT TYPE STRING,
LUNR TYPE STRING,
VERNR TYPE STRING,
OBJNR TYPE STRING,
STXT TYPE STRING,
LFLG TYPE STRING,
REJCFLG TYPE STRING,
REFOBJ TYPE STRING,
CRNAME TYPE STRING,
CRDATE TYPE STRING,
CRTIME TYPE STRING,
CHNAME TYPE STRING,
CHDATE TYPE STRING,
CHTIME TYPE STRING,END OF T_EKKO_STR.
DATA: WA_WCAK_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_WCAK_STR-MANDT sy-vline 
WA_WCAK_STR-LUNR sy-vline 
WA_WCAK_STR-VERNR sy-vline 
WA_WCAK_STR-OBJNR sy-vline 
WA_WCAK_STR-STXT sy-vline 
WA_WCAK_STR-LFLG sy-vline 
WA_WCAK_STR-REJCFLG sy-vline 
WA_WCAK_STR-REFOBJ sy-vline 
WA_WCAK_STR-CRNAME sy-vline 
WA_WCAK_STR-CRDATE sy-vline 
WA_WCAK_STR-CRTIME sy-vline 
WA_WCAK_STR-CHNAME sy-vline 
WA_WCAK_STR-CHDATE sy-vline 
WA_WCAK_STR-CHTIME sy-vline      INTO ld_text SEPARATED BY SPACE.

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