ABAP Select data from SAP table RKMESS into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM RKMESS
*  INTO TABLE @DATA(IT_RKMESS2).
*--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_RKMESS INDEX 1 INTO DATA(WA_RKMESS2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<RKMESS>-MANDT = 1.
<RKMESS>-ID = 1.
<RKMESS>-LOGSYS = 1.
<RKMESS>-LOG_HANDLE = 1.
<RKMESS>-SDATE = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_RKMESS-EDATE, sy-vline,
  WA_RKMESS-STIME, sy-vline,
  WA_RKMESS-ETIME, sy-vline,
  WA_RKMESS-APLSTAT, sy-vline,
  WA_RKMESS-STATUS_ICON, sy-vline,
  WA_RKMESS-UNAME, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_RKMESS 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_RKMESS 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_RKMESS INTO WA_RKMESS.


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

*Conversion exit MODAT, internal->external for field SDATE
CALL FUNCTION 'CONVERSION_EXIT_MODAT_OUTPUT'
  EXPORTING
    input =                      WA_RKMESS-SDATE
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_RKMESS-SDATE.
WRITE:/ 'New Value:', ld_input.

*Conversion exit MODAT, internal->external for field EDATE
CALL FUNCTION 'CONVERSION_EXIT_MODAT_OUTPUT'
  EXPORTING
    input =                      WA_RKMESS-EDATE
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_RKMESS-EDATE.
WRITE:/ 'New Value:', ld_input.

*Conversion exit TIMLO, internal->external for field STIME
CALL FUNCTION 'CONVERSION_EXIT_TIMLO_OUTPUT'
  EXPORTING
    input =                      WA_RKMESS-STIME
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_RKMESS-STIME.
WRITE:/ 'New Value:', ld_input.

*Conversion exit TIMLO, internal->external for field ETIME
CALL FUNCTION 'CONVERSION_EXIT_TIMLO_OUTPUT'
  EXPORTING
    input =                      WA_RKMESS-ETIME
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_RKMESS-ETIME.
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_RKMESS_STR, 
MANDT TYPE STRING,
ID TYPE STRING,
LOGSYS TYPE STRING,
LOG_HANDLE TYPE STRING,
SDATE TYPE STRING,
EDATE TYPE STRING,
STIME TYPE STRING,
ETIME TYPE STRING,
APLSTAT TYPE STRING,
STATUS_ICON TYPE STRING,
UNAME TYPE STRING,
IDTYPE TYPE STRING,
FUNCTION TYPE STRING,
TCODE TYPE STRING,
ACTIVITY TYPE STRING,
VARIANTE TYPE STRING,
REPID TYPE STRING,
APPLICATION TYPE STRING,
MESSAGEFLAG TYPE STRING,END OF T_EKKO_STR.
DATA: WA_RKMESS_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_RKMESS_STR-MANDT sy-vline 
WA_RKMESS_STR-ID sy-vline 
WA_RKMESS_STR-LOGSYS sy-vline 
WA_RKMESS_STR-LOG_HANDLE sy-vline 
WA_RKMESS_STR-SDATE sy-vline 
WA_RKMESS_STR-EDATE sy-vline 
WA_RKMESS_STR-STIME sy-vline 
WA_RKMESS_STR-ETIME sy-vline 
WA_RKMESS_STR-APLSTAT sy-vline 
WA_RKMESS_STR-STATUS_ICON sy-vline 
WA_RKMESS_STR-UNAME sy-vline 
WA_RKMESS_STR-IDTYPE sy-vline 
WA_RKMESS_STR-FUNCTION sy-vline 
WA_RKMESS_STR-TCODE sy-vline 
WA_RKMESS_STR-ACTIVITY sy-vline 
WA_RKMESS_STR-VARIANTE sy-vline 
WA_RKMESS_STR-REPID sy-vline 
WA_RKMESS_STR-APPLICATION sy-vline 
WA_RKMESS_STR-MESSAGEFLAG sy-vline      INTO ld_text SEPARATED BY SPACE.

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