ABAP Select data from SAP table RMCHGDOC_ALV into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM RMCHGDOC_ALV
*  INTO TABLE @DATA(IT_RMCHGDOC_ALV2).
*--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_RMCHGDOC_ALV INDEX 1 INTO DATA(WA_RMCHGDOC_ALV2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<RMCHGDOC_ALV>-CHDOC = 1.
<RMCHGDOC_ALV>-LINE = 1.
<RMCHGDOC_ALV>-POSNR = 1.
<RMCHGDOC_ALV>-DOCCH = 1.
<RMCHGDOC_ALV>-CUSER = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_RMCHGDOC_ALV-CDATE, sy-vline,
  WA_RMCHGDOC_ALV-CTIME, sy-vline,
  WA_RMCHGDOC_ALV-CTCODE, sy-vline,
  WA_RMCHGDOC_ALV-COLD, sy-vline,
  WA_RMCHGDOC_ALV-CNEW, sy-vline,
  WA_RMCHGDOC_ALV-TNAME, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_RMCHGDOC_ALV 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_RMCHGDOC_ALV 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_RMCHGDOC_ALV INTO WA_RMCHGDOC_ALV.


*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_RMCHGDOC_ALV_STR, 
CHDOC TYPE STRING,
LINE TYPE STRING,
POSNR TYPE STRING,
DOCCH TYPE STRING,
CUSER TYPE STRING,
CDATE TYPE STRING,
CTIME TYPE STRING,
CTCODE TYPE STRING,
COLD TYPE STRING,
CNEW TYPE STRING,
TNAME TYPE STRING,
FNAME TYPE STRING,END OF T_EKKO_STR.
DATA: WA_RMCHGDOC_ALV_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_RMCHGDOC_ALV_STR-CHDOC sy-vline 
WA_RMCHGDOC_ALV_STR-LINE sy-vline 
WA_RMCHGDOC_ALV_STR-POSNR sy-vline 
WA_RMCHGDOC_ALV_STR-DOCCH sy-vline 
WA_RMCHGDOC_ALV_STR-CUSER sy-vline 
WA_RMCHGDOC_ALV_STR-CDATE sy-vline 
WA_RMCHGDOC_ALV_STR-CTIME sy-vline 
WA_RMCHGDOC_ALV_STR-CTCODE sy-vline 
WA_RMCHGDOC_ALV_STR-COLD sy-vline 
WA_RMCHGDOC_ALV_STR-CNEW sy-vline 
WA_RMCHGDOC_ALV_STR-TNAME sy-vline 
WA_RMCHGDOC_ALV_STR-FNAME sy-vline      INTO ld_text SEPARATED BY SPACE.

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