ABAP Select data from SAP table RN201 into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP RN201 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 RN201. 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 RN201 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_RN201 TYPE STANDARD TABLE OF RN201,
      WA_RN201 TYPE RN201,
      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: <RN201> TYPE RN201.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_RN201.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM RN201
  INTO TABLE IT_RN201.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM RN201
*  INTO TABLE @DATA(IT_RN2012).
*--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_RN201 INDEX 1 INTO DATA(WA_RN2012).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_RN201 ASSIGNING <RN201>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<RN201>-MANDT = 1.
<RN201>-DOKAR = 1.
<RN201>-DOKNR = 1.
<RN201>-DOKVR = 1.
<RN201>-DOKTL = 1.

ENDLOOP.

LOOP AT IT_RN201 INTO WA_RN201.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_RN201-LT01, sy-vline,
  WA_RN201-LT02, sy-vline,
  WA_RN201-LT03, sy-vline,
  WA_RN201-TXTTOTAL, sy-vline,
  WA_RN201-LANGTEXT, sy-vline,
  WA_RN201-MAS_HTML, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_RN201 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_RN201 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_RN201 INTO WA_RN201.


*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 DOKNR
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_RN201-DOKNR
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_RN201-DOKNR.
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_RN201_STR, 
MANDT TYPE STRING,
DOKAR TYPE STRING,
DOKNR TYPE STRING,
DOKVR TYPE STRING,
DOKTL TYPE STRING,
LT01 TYPE STRING,
LT02 TYPE STRING,
LT03 TYPE STRING,
TXTTOTAL TYPE STRING,
LANGTEXT TYPE STRING,
MAS_HTML TYPE STRING,
RZ_BILD TYPE STRING,
UPDKZ TYPE STRING,END OF T_EKKO_STR.
DATA: WA_RN201_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_RN201_STR-MANDT sy-vline 
WA_RN201_STR-DOKAR sy-vline 
WA_RN201_STR-DOKNR sy-vline 
WA_RN201_STR-DOKVR sy-vline 
WA_RN201_STR-DOKTL sy-vline 
WA_RN201_STR-LT01 sy-vline 
WA_RN201_STR-LT02 sy-vline 
WA_RN201_STR-LT03 sy-vline 
WA_RN201_STR-TXTTOTAL sy-vline 
WA_RN201_STR-LANGTEXT sy-vline 
WA_RN201_STR-MAS_HTML sy-vline 
WA_RN201_STR-RZ_BILD sy-vline 
WA_RN201_STR-UPDKZ sy-vline      INTO ld_text SEPARATED BY SPACE.

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