ABAP Select data from SAP table HEADNOLD into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM HEADNOLD
*  INTO TABLE @DATA(IT_HEADNOLD2).
*--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_HEADNOLD INDEX 1 INTO DATA(WA_HEADNOLD2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<HEADNOLD>-RCSZK = 1.
<HEADNOLD>-RNAME = 1.
<HEADNOLD>-TABNAME = 1.
<HEADNOLD>-FIELDNAME = 1.
<HEADNOLD>-POSITION = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_HEADNOLD-OFFSET, sy-vline,
  WA_HEADNOLD-LENG, sy-vline,
  WA_HEADNOLD-INTLEN, sy-vline,
  WA_HEADNOLD-DECIMALS, sy-vline,
  WA_HEADNOLD-INTTYPE, sy-vline,
  WA_HEADNOLD-CONVEXIT, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_HEADNOLD 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_HEADNOLD 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_HEADNOLD INTO WA_HEADNOLD.


*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 DTYPE, internal->external for field DATATYPE
CALL FUNCTION 'CONVERSION_EXIT_DTYPE_OUTPUT'
  EXPORTING
    input =                      WA_HEADNOLD-DATATYPE
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_HEADNOLD-DATATYPE.
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_HEADNOLD_STR, 
RCSZK TYPE STRING,
RNAME TYPE STRING,
TABNAME TYPE STRING,
FIELDNAME TYPE STRING,
POSITION TYPE STRING,
OFFSET TYPE STRING,
LENG TYPE STRING,
INTLEN TYPE STRING,
DECIMALS TYPE STRING,
INTTYPE TYPE STRING,
CONVEXIT TYPE STRING,
LOWERCASE TYPE STRING,
KEYFLAG TYPE STRING,
SIGN TYPE STRING,
DATATYPE TYPE STRING,END OF T_EKKO_STR.
DATA: WA_HEADNOLD_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_HEADNOLD_STR-RCSZK sy-vline 
WA_HEADNOLD_STR-RNAME sy-vline 
WA_HEADNOLD_STR-TABNAME sy-vline 
WA_HEADNOLD_STR-FIELDNAME sy-vline 
WA_HEADNOLD_STR-POSITION sy-vline 
WA_HEADNOLD_STR-OFFSET sy-vline 
WA_HEADNOLD_STR-LENG sy-vline 
WA_HEADNOLD_STR-INTLEN sy-vline 
WA_HEADNOLD_STR-DECIMALS sy-vline 
WA_HEADNOLD_STR-INTTYPE sy-vline 
WA_HEADNOLD_STR-CONVEXIT sy-vline 
WA_HEADNOLD_STR-LOWERCASE sy-vline 
WA_HEADNOLD_STR-KEYFLAG sy-vline 
WA_HEADNOLD_STR-SIGN sy-vline 
WA_HEADNOLD_STR-DATATYPE sy-vline      INTO ld_text SEPARATED BY SPACE.

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