ABAP Select data from SAP table M_MCNKAX into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP M_MCNKAX 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_MCNKAX. 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_MCNKAX 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_MCNKAX TYPE STANDARD TABLE OF M_MCNKAX,
      WA_M_MCNKAX TYPE M_MCNKAX,
      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_MCNKAX> TYPE M_MCNKAX.

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM M_MCNKAX
*  INTO TABLE @DATA(IT_M_MCNKAX2).
*--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_MCNKAX INDEX 1 INTO DATA(WA_M_MCNKAX2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<M_MCNKAX>-MANDT = 1.
<M_MCNKAX>-VVABBLN = 1.
<M_MCNKAX>-ABBLNTEXT = 1.
<M_MCNKAX>-RNKGR = 1.
<M_MCNKAX>-SANPNR = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_M_MCNKAX-DVONPER, sy-vline,
  WA_M_MCNKAX-DBISPER, sy-vline,
  WA_M_MCNKAX-RERF, sy-vline,
  WA_M_MCNKAX-DERF, sy-vline,
  WA_M_MCNKAX-TERF, sy-vline,
  WA_M_MCNKAX-BUDAT, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_M_MCNKAX 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_MCNKAX 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_MCNKAX INTO WA_M_MCNKAX.


*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_M_MCNKAX_STR, 
MANDT TYPE STRING,
VVABBLN TYPE STRING,
ABBLNTEXT TYPE STRING,
RNKGR TYPE STRING,
SANPNR TYPE STRING,
DVONPER TYPE STRING,
DBISPER TYPE STRING,
RERF TYPE STRING,
DERF TYPE STRING,
TERF TYPE STRING,
BUDAT TYPE STRING,
BLDAT TYPE STRING,
MONAT TYPE STRING,
JNKAVVAE TYPE STRING,END OF T_EKKO_STR.
DATA: WA_M_MCNKAX_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_MCNKAX_STR-MANDT sy-vline 
WA_M_MCNKAX_STR-VVABBLN sy-vline 
WA_M_MCNKAX_STR-ABBLNTEXT sy-vline 
WA_M_MCNKAX_STR-RNKGR sy-vline 
WA_M_MCNKAX_STR-SANPNR sy-vline 
WA_M_MCNKAX_STR-DVONPER sy-vline 
WA_M_MCNKAX_STR-DBISPER sy-vline 
WA_M_MCNKAX_STR-RERF sy-vline 
WA_M_MCNKAX_STR-DERF sy-vline 
WA_M_MCNKAX_STR-TERF sy-vline 
WA_M_MCNKAX_STR-BUDAT sy-vline 
WA_M_MCNKAX_STR-BLDAT sy-vline 
WA_M_MCNKAX_STR-MONAT sy-vline 
WA_M_MCNKAX_STR-JNKAVVAE sy-vline      INTO ld_text SEPARATED BY SPACE.

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