ABAP Select data from SAP table /MRE/SD_HEADER_DCN into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP /MRE/SD_HEADER_DCN 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 /MRE/SD_HEADER_DCN. 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 /MRE/SD_HEADER_DCN 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_/MRE/SD_HEADER_DCN TYPE STANDARD TABLE OF /MRE/SD_HEADER_DCN,
      WA_/MRE/SD_HEADER_DCN TYPE /MRE/SD_HEADER_DCN,
      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: </MRE/SD_HEADER_DCN> TYPE /MRE/SD_HEADER_DCN.

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

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM /MRE/SD_HEADER_DCN
  INTO TABLE IT_/MRE/SD_HEADER_DCN.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM /MRE/SD_HEADER_DCN
*  INTO TABLE @DATA(IT_/MRE/SD_HEADER_DCN2).
*--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_/MRE/SD_HEADER_DCN INDEX 1 INTO DATA(WA_/MRE/SD_HEADER_DCN2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_/MRE/SD_HEADER_DCN ASSIGNING </MRE/SD_HEADER_DCN>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
</MRE/SD_HEADER_DCN>-DOC_NUMBER = 1.
</MRE/SD_HEADER_DCN>-DOC_TYPE = 1.
</MRE/SD_HEADER_DCN>-SD_DOC_CAT = 1.
</MRE/SD_HEADER_DCN>-DOC_DATE = 1.
</MRE/SD_HEADER_DCN>-REQ_DATE_H = 1.

ENDLOOP.

LOOP AT IT_/MRE/SD_HEADER_DCN INTO WA_/MRE/SD_HEADER_DCN.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_/MRE/SD_HEADER_DCN-PRICE_DATE, sy-vline,
  WA_/MRE/SD_HEADER_DCN-PRC_STAT_H, sy-vline,
  WA_/MRE/SD_HEADER_DCN-DELIV_STAT, sy-vline,
  WA_/MRE/SD_HEADER_DCN-OVERALLREJ, sy-vline,
  WA_/MRE/SD_HEADER_DCN-ORD_REASON, sy-vline,
  WA_/MRE/SD_HEADER_DCN-SALES_ORG, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_/MRE/SD_HEADER_DCN 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_/MRE/SD_HEADER_DCN 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_/MRE/SD_HEADER_DCN INTO WA_/MRE/SD_HEADER_DCN.


*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 DOC_NUMBER
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_/MRE/SD_HEADER_DCN-DOC_NUMBER
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_/MRE/SD_HEADER_DCN-DOC_NUMBER.
WRITE:/ 'New Value:', ld_input.

*Conversion exit AUART, internal->external for field DOC_TYPE
CALL FUNCTION 'CONVERSION_EXIT_AUART_OUTPUT'
  EXPORTING
    input =                      WA_/MRE/SD_HEADER_DCN-DOC_TYPE
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_/MRE/SD_HEADER_DCN-DOC_TYPE.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field LOGSYS
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_/MRE/SD_HEADER_DCN-LOGSYS
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_/MRE/SD_HEADER_DCN-LOGSYS.
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_/MRE/SD_HEADER_DCN_STR, 
DOC_NUMBER TYPE STRING,
DOC_TYPE TYPE STRING,
SD_DOC_CAT TYPE STRING,
DOC_DATE TYPE STRING,
REQ_DATE_H TYPE STRING,
PRICE_DATE TYPE STRING,
PRC_STAT_H TYPE STRING,
DELIV_STAT TYPE STRING,
OVERALLREJ TYPE STRING,
ORD_REASON TYPE STRING,
SALES_ORG TYPE STRING,
DISTR_CHAN TYPE STRING,
DIVISION TYPE STRING,
GROSS_VALUE TYPE STRING,
DISCOUNT TYPE STRING,
NET_VALUE TYPE STRING,
SURCHG_FEE TYPE STRING,
TAX_AMOUNT TYPE STRING,
TOTAL TYPE STRING,
CURRENCY TYPE STRING,
PRE_ORDER TYPE STRING,
SIMULATION_GUID TYPE STRING,
LOGSYS TYPE STRING,
CAMPAIGN TYPE STRING,
SY_USER TYPE STRING,
OBJECT_GUID TYPE STRING,END OF T_EKKO_STR.
DATA: WA_/MRE/SD_HEADER_DCN_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_/MRE/SD_HEADER_DCN_STR-DOC_NUMBER sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-DOC_TYPE sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-SD_DOC_CAT sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-DOC_DATE sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-REQ_DATE_H sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-PRICE_DATE sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-PRC_STAT_H sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-DELIV_STAT sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-OVERALLREJ sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-ORD_REASON sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-SALES_ORG sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-DISTR_CHAN sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-DIVISION sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-GROSS_VALUE sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-DISCOUNT sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-NET_VALUE sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-SURCHG_FEE sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-TAX_AMOUNT sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-TOTAL sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-CURRENCY sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-PRE_ORDER sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-SIMULATION_GUID sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-LOGSYS sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-CAMPAIGN sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-SY_USER sy-vline 
WA_/MRE/SD_HEADER_DCN_STR-OBJECT_GUID sy-vline      INTO ld_text SEPARATED BY SPACE.

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