ABAP Select data from SAP table MRCHDS_CAT_D into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM MRCHDS_CAT_D
*  INTO TABLE @DATA(IT_MRCHDS_CAT_D2).
*--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_MRCHDS_CAT_D INDEX 1 INTO DATA(WA_MRCHDS_CAT_D2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<MRCHDS_CAT_D>-MANDT = 1.
<MRCHDS_CAT_D>-MERCHANDISECATEGORY = 1.
<MRCHDS_CAT_D>-AUTHORIZATIONGROUP = 1.
<MRCHDS_CAT_D>-CONTACTPERSONSTDDEPARTMENT = 1.
<MRCHDS_CAT_D>-DIVISION = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_MRCHDS_CAT_D-MATERIALGROUPREFMATERIAL, sy-vline,
  WA_MRCHDS_CAT_D-VALUATIONCLASS, sy-vline,
  WA_MRCHDS_CAT_D-PURCHASINGVALUEKEY, sy-vline,
  WA_MRCHDS_CAT_D-LASTCHANGEDATETIME, sy-vline,
  WA_MRCHDS_CAT_D-MRCHDSCATEGORYHIERARCHYNODE, sy-vline,
  WA_MRCHDS_CAT_D-DRAFTENTITYCREATIONDATETIME, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_MRCHDS_CAT_D 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_MRCHDS_CAT_D 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_MRCHDS_CAT_D INTO WA_MRCHDS_CAT_D.


*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 MATN1, internal->external for field MATERIALGROUPREFMATERIAL
CALL FUNCTION 'CONVERSION_EXIT_MATN1_OUTPUT'
  EXPORTING
    input =                      WA_MRCHDS_CAT_D-MATERIALGROUPREFMATERIAL
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_MRCHDS_CAT_D-MATERIALGROUPREFMATERIAL.
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_MRCHDS_CAT_D_STR, 
MANDT TYPE STRING,
MERCHANDISECATEGORY TYPE STRING,
AUTHORIZATIONGROUP TYPE STRING,
CONTACTPERSONSTDDEPARTMENT TYPE STRING,
DIVISION TYPE STRING,
MATERIALGROUPREFMATERIAL TYPE STRING,
VALUATIONCLASS TYPE STRING,
PURCHASINGVALUEKEY TYPE STRING,
LASTCHANGEDATETIME TYPE STRING,
MRCHDSCATEGORYHIERARCHYNODE TYPE STRING,
DRAFTENTITYCREATIONDATETIME TYPE STRING,
DRAFTENTITYLASTCHANGEDATETIME TYPE STRING,
DRAFTADMINISTRATIVEDATAUUID TYPE STRING,
DRAFTENTITYOPERATIONCODE TYPE STRING,
HASACTIVEENTITY TYPE STRING,
DRAFTFIELDCHANGES TYPE STRING,END OF T_EKKO_STR.
DATA: WA_MRCHDS_CAT_D_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_MRCHDS_CAT_D_STR-MANDT sy-vline 
WA_MRCHDS_CAT_D_STR-MERCHANDISECATEGORY sy-vline 
WA_MRCHDS_CAT_D_STR-AUTHORIZATIONGROUP sy-vline 
WA_MRCHDS_CAT_D_STR-CONTACTPERSONSTDDEPARTMENT sy-vline 
WA_MRCHDS_CAT_D_STR-DIVISION sy-vline 
WA_MRCHDS_CAT_D_STR-MATERIALGROUPREFMATERIAL sy-vline 
WA_MRCHDS_CAT_D_STR-VALUATIONCLASS sy-vline 
WA_MRCHDS_CAT_D_STR-PURCHASINGVALUEKEY sy-vline 
WA_MRCHDS_CAT_D_STR-LASTCHANGEDATETIME sy-vline 
WA_MRCHDS_CAT_D_STR-MRCHDSCATEGORYHIERARCHYNODE sy-vline 
WA_MRCHDS_CAT_D_STR-DRAFTENTITYCREATIONDATETIME sy-vline 
WA_MRCHDS_CAT_D_STR-DRAFTENTITYLASTCHANGEDATETIME sy-vline 
WA_MRCHDS_CAT_D_STR-DRAFTADMINISTRATIVEDATAUUID sy-vline 
WA_MRCHDS_CAT_D_STR-DRAFTENTITYOPERATIONCODE sy-vline 
WA_MRCHDS_CAT_D_STR-HASACTIVEENTITY sy-vline 
WA_MRCHDS_CAT_D_STR-DRAFTFIELDCHANGES sy-vline      INTO ld_text SEPARATED BY SPACE.

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