ABAP Select data from SAP table RNREL into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM RNREL
*  INTO TABLE @DATA(IT_RNREL2).
*--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_RNREL INDEX 1 INTO DATA(WA_RNREL2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<RNREL>-MANDT = 1.
<RNREL>-AKTION = 1.
<RNREL>-GPART1 = 1.
<RNREL>-RGPART2 = 1.
<RNREL>-EINRI = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_RNREL-FALAR, sy-vline,
  WA_RNREL-BEWTY, sy-vline,
  WA_RNREL-BWART, sy-vline,
  WA_RNREL-ABART, sy-vline,
  WA_RNREL-GPART2, sy-vline,
  WA_RNREL-UPUSR, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_RNREL 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_RNREL 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_RNREL INTO WA_RNREL.


*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 GPART1
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_RNREL-GPART1
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_RNREL-GPART1.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field EINRI
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_RNREL-EINRI
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_RNREL-EINRI.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field ABART
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_RNREL-ABART
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_RNREL-ABART.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field GPART2
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_RNREL-GPART2
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_RNREL-GPART2.
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_RNREL_STR, 
MANDT TYPE STRING,
AKTION TYPE STRING,
GPART1 TYPE STRING,
RGPART2 TYPE STRING,
EINRI TYPE STRING,
FALAR TYPE STRING,
BEWTY TYPE STRING,
BWART TYPE STRING,
ABART TYPE STRING,
GPART2 TYPE STRING,
UPUSR TYPE STRING,
UPDAT TYPE STRING,END OF T_EKKO_STR.
DATA: WA_RNREL_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_RNREL_STR-MANDT sy-vline 
WA_RNREL_STR-AKTION sy-vline 
WA_RNREL_STR-GPART1 sy-vline 
WA_RNREL_STR-RGPART2 sy-vline 
WA_RNREL_STR-EINRI sy-vline 
WA_RNREL_STR-FALAR sy-vline 
WA_RNREL_STR-BEWTY sy-vline 
WA_RNREL_STR-BWART sy-vline 
WA_RNREL_STR-ABART sy-vline 
WA_RNREL_STR-GPART2 sy-vline 
WA_RNREL_STR-UPUSR sy-vline 
WA_RNREL_STR-UPDAT sy-vline      INTO ld_text SEPARATED BY SPACE.

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